A surprising number of "broken" computers aren't broken. A bad charger, a monitor cable in the wrong port, a stuck update or a full drive can look exactly like a hardware failure. This guide walks through the most common problems one symptom at a time, with the checks worth doing at home and the built-in Windows and Mac tools that actually help. If one of these fixes it, great. If not, you'll come in with useful information that gets you a faster fix.
Back Up Before You Troubleshoot
If the computer still turns on, copy your important files to an external drive or the cloud before trying anything else. Several fixes below, like resets and reinstalls, can erase data. A computer that's acting up can also fail completely at any point.
It Won't Turn On at All
Laptops
- Check the charger
Look for a light on the charger brick or the laptop's charging port. Try a different outlet. Check the cable for fraying or bends near the connector. If you have a compatible charger, try it. Chargers fail more often than laptops do.
- Do a power drain
Unplug the charger and hold the power button down for 30 seconds. Then plug back in and try again. This clears leftover power that can stop a laptop from starting.
- Let a dead battery charge
A fully drained battery can take a while before the laptop will even try to start. Leave it plugged in for 30 minutes, then try again.
- Check if it's really off
Listen for fans, look for keyboard backlights or caps lock lights, and try an external monitor. If an external monitor works, the problem is the laptop's screen, not the whole computer.
Desktops
- Check every power connection
The power cable at the wall and at the back of the computer, the power strip, and the switch on the back of the power supply itself (it should be on the "I" side).
- Try a different outlet and cable
Plug the computer directly into a wall outlet, skipping the power strip. If you have a spare power cable, try it.
- Look for any sign of life
Fans spinning, lights on the motherboard, a power button light. Nothing at all points to the power supply or the power button. Fans spinning but nothing on screen is a different problem, covered next.
It Turns On but There's Nothing on the Screen
This is one of the most common "dead computer" calls, and it's often simple.
- Desktop monitor cable in the wrong port. If your desktop has a graphics card, the monitor needs to plug into the ports on the graphics card, lower on the back, not the ones on the motherboard near the USB ports. This catches a lot of people after moving a PC.
- Check the monitor itself. Is it on? Is it set to the right input (HDMI 1, DisplayPort and so on)? Try a different cable.
- Laptop screen black but the computer is running. Try an external monitor. On Windows, press Windows + P to switch display modes. Shine a flashlight at the screen: if you can faintly see an image, the backlight has failed.
- Listen for beeps and watch for flashing lights. Many computers signal problems this way. A desktop may beep in a pattern, and many motherboards have small diagnostic lights labeled CPU, DRAM, VGA and BOOT. Dell, HP and Lenovo laptops often blink the power or caps lock light in a pattern. Write down the pattern or take a video. It tells a tech exactly where to look.
It Starts but Won't Boot Into Windows or macOS
Windows
- Let Automatic Repair run. If Windows fails to start a few times in a row, it opens recovery options on its own.
- Try Startup Repair from the recovery menu (Troubleshoot > Advanced options).
- Boot into Safe Mode from the same menu. If Safe Mode works, a driver or program is usually the cause.
- Use System Restore to roll back to a point before the problem started. It doesn't touch your personal files.
- Uninstall the latest update from the recovery menu if the problem started right after an update.
If Windows does start, these built-in tools can repair damaged system files. Open Command Prompt as administrator and run:
sfc /scannowto check and repair Windows system filesDISM /Online /Cleanup-Image /RestoreHealthto repair the Windows image that sfc uses
Mac
- Start in Safe Mode. On Apple silicon, shut down, hold the power button until you see startup options, select your disk, then hold Shift and choose Continue in Safe Mode. On Intel Macs, hold Shift while starting up.
- Run Disk Utility First Aid from macOS Recovery. On Apple silicon, hold the power button at startup and choose Options. On Intel Macs, hold Command + R.
- Reinstall macOS from Recovery. This reinstalls the system without erasing your files, but back up first if you can.
- Run Apple Diagnostics to check hardware. On Apple silicon, hold the power button, then press Command + D at the startup options. On Intel Macs, hold D at startup.
- Intel Macs only: resetting NVRAM (hold Option + Command + P + R at startup) can fix some startup, display and sound issues. Apple silicon Macs handle this automatically.
It's Running Slow
Not sleep, not closing the lid. A full restart. On Windows, Fast Startup means shutting down isn't always a true restart, so use Restart.
Open Task Manager (Ctrl+Shift+Esc) or Activity Monitor on a Mac and sort by CPU, memory and disk. Close anything heavy you don't need.
A drive that's nearly full slows everything down. Clear out downloads, old installers and large files you don't need, and empty the trash.
On Windows, Task Manager's Startup tab. On a Mac, System Settings > General > Login Items. Turn off anything that doesn't need to run all the time.
Let Windows Update or macOS updates finish. A half-installed update is a common cause of slowdowns.
Run a full scan with Microsoft Defender on Windows. A computer that's suddenly slow with a busy fan can be running something it shouldn't.
Slow and hot usually means it's throttling to cool down. Use it on a hard surface and make sure the vents are clear.
If Task Manager shows the disk stuck near 100% and it says HDD, the hard drive is the bottleneck, and an SSD fixes it. If memory stays nearly full, more RAM helps.
Still slow?An SSD or RAM upgrade is often faster and cheaper than a new computer.It Freezes, Crashes or Shows Blue Screens
- Write down the stop code. Windows blue screens show a code like
MEMORY_MANAGEMENTorCRITICAL_PROCESS_DIED, plus a QR code. Take a photo. - Check Reliability Monitor. Search Windows for "Reliability Monitor." It shows a timeline of crashes and what failed.
- Look for a pattern. Only in games? Only after it's been on a while? Only with a certain program or device plugged in?
- Undo recent changes. New software, a driver or an update right before the crashes started is a strong clue.
- Unplug accessories. A faulty dock, USB device or external drive can cause crashes.
- Test memory. Windows has a built-in Windows Memory Diagnostic tool. Errors there point to bad RAM.
Crashes that keep coming back usually point to failing memory, a dying drive, overheating or a power supply problem. Those need hands-on testing.
The Battery Won't Charge or Drains Fast
- Try a different outlet and charger, and check the charging port for lint. Gently clean it out with a wooden toothpick if needed.
- Check battery health. On a Mac, go to System Settings > Battery and look at Battery Health. On Windows, open Command Prompt and run
powercfg /batteryreport, then open the report file it creates. It shows the battery's original capacity next to what it holds now. - "Plugged in, not charging" on Windows can be a charging limit setting in the laptop maker's software, which some laptops use to protect the battery.
- A battery that's lost much of its original capacity is worn out and worth replacing.
- A swollen battery needs to come out now. Stop using and charging the laptop.
No Wi-Fi or Internet
- Restart the router and the computer
- Turn Wi-Fi off and on, and check airplane mode
- Forget the network and reconnect
- Check if other devices can connect
- Try a wired connection
- Run Windows' network troubleshooter
- Other devices work fine, yours doesn't
- The Wi-Fi option is missing entirely
- It only works right next to the router
- It started after a drop or a spill
- It keeps dropping after a reinstall
No Sound
- Check the volume and mute, and the output device. On Windows, click the speaker icon and pick the right output. On a Mac, System Settings > Sound.
- Unplug headphones and Bluetooth devices. Audio often gets stuck going to a device that isn't there.
- Restart. On Windows, check for audio driver updates from your laptop maker.
- Sound through headphones but not speakers, or crackling and popping, usually points to the speakers themselves.
Keyboard or Trackpad Problems
- Restart first. Then plug in a USB keyboard or mouse. If the external one works, the built-in one has a hardware problem.
- Clean stuck keys with compressed air, holding the laptop at an angle. Don't pry keycaps off; the clips break easily.
- Trackpad suddenly not working on a Windows laptop: check whether it's been turned off with a function key, or in Settings > Bluetooth & devices > Touchpad.
- A trackpad that clicks on its own, feels raised or won't click can be a sign of a swelling battery underneath. Stop using it and get it checked.
Signs It's Time to Stop Troubleshooting
Unplug it immediately and don't turn it back on.
The trackpad is lifting, the case is bulging or it rocks on a flat table. Stop using it and don't charge it.
That's a failing hard drive. Every time it runs, the chance of recovering your files drops. Turn it off.
Power it off and unplug it. Don't dry it with heat or rice. Bring it in quickly.
At that point the easy causes are ruled out, and the problem needs testing with the right tools and parts.
What to Bring When You Come In
- The computer and its charger (and any dock or adapter it normally uses)
- Your password, if you're comfortable sharing it, so we can test properly
- A list of what you've tried, and photos of error messages or blue screens
- Any beep patterns or blinking light codes you noticed
- What changed right before it broke: a drop, a spill, an update, a move
Frequently Asked Questions
Why won't my laptop turn on even when it's plugged in?
The most common causes are a failed charger, a bad charging port, a fully drained battery, or leftover power that needs clearing. Try a different charger, leave it plugged in for 30 minutes, and hold the power button for 30 seconds with the charger unplugged. If it still won't start, it needs hands-on testing.
My desktop turns on but the monitor says no signal. What's wrong?
Check that the monitor cable is plugged into the graphics card ports, not the motherboard ports, if your PC has a graphics card. Then check the monitor's input setting and try a different cable. If it still shows no signal, watch for beeps or motherboard lights and bring it in.
What do the beeps or blinking lights mean when my computer starts?
They're diagnostic codes. Each pattern points to a specific part, like memory, the graphics card or the motherboard. Write down or record the pattern and bring it with you.
Is it safe to keep using a computer that keeps crashing?
It's risky if your files aren't backed up. Repeated crashes can point to a failing drive or memory, and things can get worse quickly. Back up what you can and get it looked at.
Should I reset my computer to fix it?
Only if everything important is backed up. A reset can fix software problems, but it erases files and programs and won't fix a hardware problem.
How do I check my laptop's battery health?
On a Mac, go to System Settings > Battery > Battery Health. On Windows, run powercfg /batteryreport in Command Prompt and open the report. Compare the design capacity to the full charge capacity.
What should I do if I spilled something on my laptop?
Turn it off right away, unplug it, and don't charge it. Don't use a hair dryer or put it in rice. Bring it in as soon as possible, since corrosion keeps spreading the longer it sits.
Do I need an appointment?
No. Walk in to either Fixoid store any day we're open, or start a repair online first so we have the details ready.
