PC Tips & Fixes

Step-by-step Windows 11 and 10 fixes, written for technicians and anyone willing to follow the menus. Blue screen stop codes, Wi-Fi and internet drops, slow performance, gaming and apps, malware, and the hardware behind them.

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All 210 guides, grouped by the kind of problem they solve. Use the filters and search above to narrow further, or jump straight into a category below.

Looking for security and malware guides?

Removing an active infection, hardening Windows 11, protecting your accounts, and locking down your router and smart home devices — all collected on one page.

Browse the security guides →

Performance & Optimization (77 guides)

Reclaim speed on a PC that has slowed down: high CPU and RAM use, disk thrashing, startup bloat, and storage that has filled up.

Plus 65 more in Performance & Optimization — use the Performance & Optimization filter at the top of the page.

Network & Internet (31 guides)

Get back online and stay there: dropped Wi-Fi, DNS errors, slow speeds, high ping, hotspots, and sharing between PCs.

Plus 19 more in Network & Internet — use the Network & Internet filter at the top of the page.

Security & Data Recovery (77 guides)

Protect what matters and get it back when something goes wrong: malware removal, backups, encryption, passwords, and deleted files.

Plus 65 more in Security & Data Recovery — use the Security & Data Recovery filter at the top of the page.

Online Safety & Scams (28 guides)

Recognise the scams that reach real people every day: phishing email, fake support calls, smishing texts, and hijacked accounts.

Plus 16 more in Online Safety & Scams — use the Online Safety & Scams filter at the top of the page.

Display & Audio (43 guides)

Fix what you see and hear: undetected monitors, flickering screens, silent speakers, crackling sound, and microphone problems.

Plus 31 more in Display & Audio — use the Display & Audio filter at the top of the page.

Browsers & Web (27 guides)

Keep the browser fast and clean: hijacked search, notification spam, runaway memory use, and checking a link before you click it.

Plus 15 more in Browsers & Web — use the Browsers & Web filter at the top of the page.

Peripherals & Devices (11 guides)

Get the things you plug in working again: mice, keyboards, printers, scanners, and the drivers behind them.

Troubleshooting & Fixes (144 guides)

Targeted fixes for specific failures: blue screen stop codes, boot loops, apps that will not open, and devices Windows stops recognising.

Plus 132 more in Troubleshooting & Fixes — use the Troubleshooting & Fixes filter at the top of the page.

Setup & Maintenance (57 guides)

Install, migrate, and keep a PC healthy: clean installs, update problems, drivers, backups, and routine upkeep.

Plus 45 more in Setup & Maintenance — use the Setup & Maintenance filter at the top of the page.

Buying & Upgrades (39 guides)

Spend well: which upgrade actually helps, how much RAM you need, choosing an SSD, and when a repair beats a replacement.

Plus 27 more in Buying & Upgrades — use the Buying & Upgrades filter at the top of the page.

Not Sure Where to Start?

Match what you are seeing to the closest symptom below, then open the guide that walks you through it. Every fix is ordered least-invasive first, so start at the top and test after each step.

SymptomLikely causeStart here
PC won’t power on or shows no displayPower supply, loose RAM, or a dead outletPC won’t turn on
Everything is slow or laggyStartup bloat and a nearly full diskSpeed up a slow PC
Blue screen crash with a stop codeA faulty driver or failing hardwareFix a blue screen
No internet even though Wi-Fi is connectedNetwork adapter or DNS problemFix no internet
No sound from speakers or headphonesWrong output device or audio driverFix no audio
Black screen after the PC bootsDisplay driver, cable, or boot faultFix a black screen

Windows 11 Errors & Stop Codes Explained

The line of capital letters on a blue screen — or the error a program throws when it refuses to start — tells you what failed. Here is what the common ones mean in plain English, each linked to the guide that fixes it. Photograph the code before your PC restarts.

  • IRQL_NOT_LESS_OR_EQUAL

    A driver tried to access memory it should not — usually a bad or outdated driver.

    Fix it →

  • MEMORY_MANAGEMENT

    Windows found a fault handling memory, often a RAM stick or a driver at fault.

    Fix it →

  • CRITICAL_PROCESS_DIED

    A process Windows cannot run without stopped, commonly from corrupt system files.

    Fix it →

  • DPC_WATCHDOG_VIOLATION

    A device or driver took too long to respond — often an old SSD firmware or driver.

    Fix it →

  • KERNEL_SECURITY_CHECK_FAILURE

    Windows detected corrupted data in the kernel, usually a driver or memory issue.

    Fix it →

  • CLOCK_WATCHDOG_TIMEOUT

    A CPU core stopped responding — often an unstable overclock or a driver fault.

    Fix it →

  • NTFS_FILE_SYSTEM

    The drive’s file system is damaged, from bad sectors or an unsafe shutdown.

    Fix it →

  • UNEXPECTED_STORE_EXCEPTION

    A core Windows component crashed, commonly tied to storage or antivirus software.

    Fix it →

  • INACCESSIBLE_BOOT_DEVICE

    Windows cannot reach the drive it boots from — often after an update or BIOS change.

    Fix it →

  • WHEA_UNCORRECTABLE_ERROR

    A physical component reported a fault that could not be fixed — genuine hardware.

    Fix it →

  • VCRUNTIME140.dll / MSVCP140.dll is missing

    A program needs the Visual C++ runtime that is not installed on the PC.

    Fix it →

  • 0xc0000142 (application error)

    An app failed to start correctly, usually from missing runtimes or corrupt files.

    Fix it →

  • DNS_PROBE_FINISHED_NO_INTERNET

    The browser cannot resolve website addresses — a DNS rather than a hardware fault.

    Fix it →

  • SYSTEM_THREAD_EXCEPTION_NOT_HANDLED

    A driver hit an error nothing caught — the failing .sys file is usually named on screen.

    Fix it →

  • KMODE_EXCEPTION_NOT_HANDLED

    A kernel-mode program failed, often tied to fast startup or a recently changed driver.

    Fix it →

  • BAD_POOL_HEADER

    A driver corrupted Windows’ kernel memory pool, commonly a security suite or bad RAM.

    Fix it →

  • PFN_LIST_CORRUPT

    Windows’ index of physical memory pages was damaged — usually failing RAM.

    Fix it →

  • KERNEL_DATA_INPAGE_ERROR

    Windows could not read data back from the drive — often an early sign of disk failure.

    Fix it →

  • 0x80070005 (access denied)

    Windows Update, the Store, or activation was refused access it needs to a file or key.

    Fix it →

  • 0x800f081f (DISM source missing)

    DISM could not find the replacement files it needs to repair Windows.

    Fix it →

  • 0x80004005 (unspecified error)

    A generic failure with no detail — the cause depends entirely on where it appeared.

    Fix it →

  • 0x80070570 (file or directory is corrupted)

    Data read back did not match what the file system expected — failing storage or bad media.

    Fix it →

  • Boot Device Not Found (3F0)

    The firmware found nothing bootable — a boot order, detection, or boot record problem.

    Fix it →

How to Use These Guides

Every fix here uses tools already built into Windows — Settings, Device Manager, Terminal, Windows Security, and the recovery environment. Nothing needs to be purchased or downloaded to follow a guide. Where a manufacturer driver or a Microsoft tool is needed, the guide links to the official source and says why.

Steps are ordered least invasive first. Start at Step 1 even when a later step looks more likely — the early steps take seconds and rule out the common causes that make the expensive ones unnecessary. Test after each step rather than applying everything at once, or you will not know what fixed it.

Anything that can affect your files is flagged before you reach it. Resets, formats, partition changes, and clean installs all say so plainly. Before starting a repair on a PC holding data you cannot lose, create a restore point and check your backup is current — a five-minute precaution that turns a bad afternoon into an inconvenience.

Most guides target Windows 11, and the majority of steps work on Windows 10 too, though some menu paths and names differ. Laptop-specific advice — charging, thermals, battery health, firmware — is called out separately wherever the answer is different from a desktop.

If you are unsure whether a fault is hardware or software, settle that first: a problem that survives Safe Mode, a driver reinstall, and a clean boot is usually hardware, and so is one that changes with temperature or load. When a crash is involved, Event Viewer often names the driver or app responsible. And before any repair on a PC holding data you cannot lose, create a restore point so almost every change stays reversible.

Common Questions

Are these Windows 11 fix guides free?
Yes. All 210 troubleshooting guides on My Technician are free to read.
Do I need to download anything to fix Windows 11?
No. Every guide uses built-in Windows tools. Our apps are optional and never required to follow a fix.
Do these fixes work on Windows 10?
Most steps apply to Windows 10 as well, though some menu names and paths differ slightly.
Will these fixes delete my files?
No. Each guide flags any step that affects your files and tells you to back up first.
How often are the guides updated?
Guides are reviewed and updated regularly to match the latest Windows 11 builds.
Which guide should I start with if my PC is just slow?
Start with the speed up a slow Windows PC guide, then check Task Manager to see whether the CPU, disk, or memory is the bottleneck. Each of those has its own targeted fix.
What is a BSOD stop code and why does it matter?
The stop code is the line of capital letters on a blue screen, such as MEMORY_MANAGEMENT or IRQL_NOT_LESS_OR_EQUAL. It identifies what failed, so it points you at the right fix instead of guessing. Photograph it before the PC restarts.
Do I need administrator rights to follow these guides?
Many steps do need an administrator account, particularly anything using Terminal (Admin), Device Manager, or Windows services. On a work machine, check with your IT team first.
Is it safe to run SFC and DISM?
Yes. Both are Microsoft tools that repair Windows system files without touching your documents, photos, or installed programs. DISM needs an internet connection to fetch replacement files.
How do I tell whether a problem is hardware or software?
If the fault survives Safe Mode, a driver reinstall, and a clean boot, it is usually hardware. Faults that vary with temperature, appear during heavy load, or produce different error codes each time also point at hardware.
Can I break Windows by following these guides?
The steps are ordered least-invasive first, and anything risky is flagged with what it affects. Creating a restore point before you start makes almost every change reversible.
Do these guides cover laptops as well as desktops?
Yes. Where the answer differs, the guide says so — battery, charging, thermal, and firmware steps are called out separately for laptops.
Why won't my PC stay asleep?
Wake timers, Fast Startup, and devices set to wake the PC (network adapters, mice, scheduled tasks) are the usual causes. Check power settings and run powercfg /lastwake in an admin terminal. See our sleep and hibernation fix guide for step-by-step help.
Why is an app blocked by Windows Firewall?
Windows blocks inbound connections on Public networks by default. Set your home network to Private, then allow the app through Settings → Windows Security → Firewall → Allow an app through firewall. See our Windows Firewall blocking apps guide for inbound rules and multiplayer fixes.
How do I get into BIOS or UEFI on a Windows 11 PC?
The reliable route is from inside Windows: Settings → System → Recovery → Advanced startup → Restart now, then Troubleshoot → Advanced options → UEFI Firmware Settings. Tapping Delete, F2, or F10 at power-on still works, but Fast Startup often leaves too small a window to catch it.
What does WHEA_UNCORRECTABLE_ERROR mean?
It means a physical component — usually the CPU, memory, or a PCIe device — reported a fault that could not be corrected, so Windows stopped. Unlike most stop codes it is genuinely hardware, and the first thing to rule out is an unstable overclock or XMP memory profile by loading firmware defaults.
My browser keeps redirecting to a search engine I did not choose — why?
That is a browser hijacker. It installs in several places at once: an extension, a modified shortcut, a scheduled task, and often an enterprise policy that locks the setting. Removing only one of them lets the others put it back, so all four have to be cleared.
How do I check whether my laptop battery needs replacing?
Run powercfg /batteryreport /output "C:\battery-report.html" in Terminal (Admin) and open the file. Divide the full charge capacity by the design capacity: above 80 per cent is healthy, below 60 per cent means the battery is worn out and worth replacing.
Why is my PC fan so loud all the time?
Constant fan noise usually means the CPU or GPU is running hot, or a background process is holding it at full load. Clear dust from the vents, check Task Manager for a process stuck near 100 per cent, and make sure air can reach the intakes. See our loud fan noise and CPU overheating guides for step-by-step cooling fixes.
What does 100% disk usage in Task Manager mean?
It means Windows is reading and writing to your drive as fast as it can, so everything else waits its turn. On older hard drives the usual culprits are Windows Search, SysMain, or a stuck update. See our 100% disk usage guide to find and stop the cause.
Why is my CPU stuck at 100%?
A single misbehaving process, a Windows Update running in the background, or malware can hold the CPU at full load. Open Task Manager, sort by CPU, and note the top process. See our 100% CPU usage guide for how to trace and fix it.
How much RAM do I need for Windows 11?
Windows 11 requires 4 GB to run, but 8 GB is the realistic minimum and 16 GB is comfortable for browsing with many tabs, office work, and light gaming. If the PC is slow and memory sits near 100 per cent, adding RAM helps — but check our high RAM usage guide first to rule out a software cause.
Why does my PC restart by itself with no warning?
Unexpected restarts are usually a blue screen crash that reboots before you can read it, an overheating CPU, or a failing power supply. Turn off automatic restart so the stop code stays on screen. See our blue screen and PC not shutting down or restarting guides for the full process.
What is the difference between Sleep, Hibernate, and Shut down?
Sleep keeps your session in memory for an instant wake but draws a little power. Hibernate saves the session to disk and uses no power, waking more slowly. Shut down closes everything and starts fresh next time. See our sleep and hibernation guide if the PC will not sleep or wake correctly.
Are registry cleaner apps safe to use?
We do not recommend them. The entries they remove rarely affect speed, and an aggressive clean can break installed programs or Windows itself. Use the built-in Disk Cleanup and Storage Sense instead — both are supported by Microsoft and safe.
How do I check which version of Windows 11 I have?
Press Windows + R, type winver, and press Enter — the box shows your edition and build number. For full hardware and system details, see our check PC specs guide.
Where do I find my BitLocker recovery key?
For a personal PC, sign in at account.microsoft.com/devices/recoverykey with the same Microsoft account used on that machine. For a work or school PC, check myaccount.microsoft.com under Devices, or ask your IT team. Match the Key ID shown on the recovery screen. There is no way to bypass BitLocker without the key — nobody, including Microsoft, can recover it for you.
Why does a blue screen name a .sys file, and what should I do with it?
That file is the driver that failed. Search the exact filename to identify which device it belongs to, then roll back or reinstall that driver in Device Manager. If no file is named, the minidump in C:\Windows\Minidump records it, and Driver Verifier can force the guilty driver to name itself.
What does it mean when Windows signs me in with a temporary profile?
Windows could not load your real profile and gave you a disposable one instead. Your files are not deleted — they are still in C:\Users under your name. Anything you save during a temporary session is erased at sign-out, so do not work in it. The fix is usually repairing the profile entry in the registry.
Can I run Hyper-V on Windows 11 Home?
No. Hyper-V requires Windows 11 Pro, Enterprise, or Education. On Home, use WSL for Linux command-line work — it is fully supported — or install VirtualBox for full virtual machines. Avoid third-party scripts that claim to enable Hyper-V on Home; they cause update failures later.