If your computer won’t start, don’t panic (yet). Here are some troubleshooting steps to take when your computer fails to boot correctly.
Reposted from PCMAG written By Whitson GordonUpdated July 21, 2021
You sit down at your computer, push the power button just like you do every day, and…nothing happens. Maybe the computer doesn’t turn on at all, maybe it powers up but shuts right down, or maybe all you get is a blue screen. There’s nothing obviously wrong here, so why won’t the computer just start? Here are some troubleshooting steps to take.
Give It More Power
(Photo: Zlata Ivleva)
If your computer isn’t turning on at all—no fans are running, no lights are blinking, and nothing appears on screen—you probably have a power issue.
Unplug your computer and plug it directly into a wall outlet you know is working, rather than a power strip or battery backup that may be failing. Make sure the power switch on the back of your power supply is flipped on, and if the outlet is connected to a light switch, make sure that switch is turned on too.
If you’re using a laptop, make sure your charger is plugged in properly and to the correct port—if it charges via USB-C, only some of the USB ports may actually provide power. A failing power supply can often cause boot problems, even if the fans and lights do turn on. So if the troubleshooting steps in this guide fail you, it might be time to replace your power supply.
Check Your Monitor
(Photo: Zlata Ivleva)
If the computer sounds like it’s turning on but you don’t see anything on the screen, the computer may be booting and the monitor just isn’t showing an image. Check to make sure your monitor is plugged in (again, try a wall outlet instead of a power strip), turned on, and set to the right input using the buttons on the side or bottom.
You’ll also want to make sure the cable connecting your monitor to your PC hasn’t come loose, become damaged, or is at fault. If you can connect another computer to your monitor and get a picture, it may be the cable that needs replacing.
If you’re using a laptop, this may sound silly, but make sure the brightness is turned up. I’ve had multiple people ask me for help with a computer that won’t start, only to find the brightness was turned all the way down, causing a black screen.
If these fixes don’t help, try plugging your PC into another monitor if you have one—or even a TV—and see if Windows shows up there. If it does, your monitor may be dead, and you need to buy a new one.
Listen for the Beep
(Photo: Michael Sexton)
When your computer boots, it may make a beeping sound—usually a single beep means everything is A-Okay. But if the computer is having trouble starting up, it may make a series of beeps (kind of like Morse code) that tell you what’s wrong.
Check the manual for your PC (or the PC’s motherboard, if you built it yourself) and figure out what the beeps mean. If you don’t have your manual, you can probably find it on the manufacturer’s website.
If your computer doesn’t beep at all, you might be out of luck—though some desktop PCs may have a header on the motherboard where you can install a cheap speaker, or even a digital display with a numerical code that corresponds to an error message.
Unplug Unnecessary USB Devices
(Photo: Nor Gal/Shutterstock)
Before continuing, unplug anything superfluous from your computer—webcams, external hard drives, USB headsets. Try booting with just a keyboard and mouse (or even without a keyboard and mouse, if in dire straits) to see if one of your USB devices is causing a conflict.
In some circumstances, it may not even be the device itself, but the port on your computer. I’ve owned a PC that couldn’t get into Windows if something was plugged into the front USB port—once booted, the ports would work fine, but it needed to be empty during the boot process. The more variables you can eliminate, the better.
Reseat the Hardware Inside
(Photo: Zlata Ivleva)
There’s a chance a component of your computer has come loose inside the case, especially if it was recently transported somewhere or if you were working inside of it.
If you’re comfortable opening your computer up, remove the side panel and make sure the components are properly seated in their respective sockets. That includes your RAM, graphics card, motherboard cables, and the CPU heatsink. Remove them completely, then plug them back in, ensuring they click in all the way.
You might also try booting without certain hardware, like the graphics card or one of the RAM sticks, in case they’re faulty. (And if it doesn’t work with one RAM stick, try the other.)
Explore the BIOS
If your computer turns on and you see the POST screen but can’t boot into Windows, certain settings may be causing a problem. For example, an error stating that your computer can’t find a bootable operating system may mean your BIOS is set to boot from the wrong drive or your overclocking settings are causing the computer to blue screen immediately.
Enter your BIOS when the POST screen appears, usually by pressing Delete, F2, or some other key to enter setup. If you’ve tweaked any of these settings recently, try changing them back.
Make sure your Boot Order is set to the correct hard drive, your RAM is recognized, and that your CPU isn’t overheating (if it’s above 90 degrees Celsius in the BIOS, something is definitely wrong). You might also turn off the Fast Boot feature, in case a recent Windows Update is conflicting with it.
If all else fails, try resetting your BIOS settings across the board using the Load Optimized Defaults option. Just be sure to snap a few photos of your BIOS settings so you can set them back if that doesn’t work.
Scan for Viruses Using a Live CD
It’s possible you have some nasty malware that’s preventing your computer from booting. But with a live environment like Hiren’s Boot CD, you can boot your computer from a CD or USB drive and scan your hard drive for malware without booting into Windows.
Download the ISO image from this page, and follow the instructions to “burn” it to a USB flash drive. Reboot your computer and access the Boot menu—usually by pressing F11, F12, or some other key defined at startup. Choose your USB drive from the boot menu, and it should boot into Hiren’s live environment.
From there, you can head into Utilities > Security and run a virus scan with ESET and a malware scan with Malwarebytes. If either program finds anything, it’ll let you know and attempt to fix it, which will hopefully allow you to boot into Windows once again.
Boot Into Safe Mode
(Illustration: Gunay Aliyeva/Getty Images)
If you’re getting the Blue Screen of Death at startup, it could be a result of a bad application, driver issue, or other hardware quirk causing problems on boot. If you can, Google the stop code that appears and see if it gives you any insight into what’s wrong.
Chances are, though, you’ll have to boot into Safe Mode to fix the problem. This used to be an easy process in Windows 7, because all you had to do was press F8 as you booted up. It is much trickier in Windows 10, but usually if you interrupt the boot process three times—say, by pressing the reset button as Windows tries to boot—it’ll take you to the Automatic Repair screen, where you can click Advanced Options.
Alternatively, you can create a Windows installation drive using another PC and boot from that directly, choosing your language and selecting Repair Your Computer when given the option. Either of these methods should eventually get you to the Choose an Option screen, where you can click Troubleshoot > Advanced Options > Startup Settings and reboot the computer. (If you don’t see the Startup Settings option, you may need to click See More Recovery Options along the bottom.)
Your computer should then give you the option to boot into Safe Mode, Safe Mode with Networking, or Safe Mode with Command Prompt. You can try any of these, though the most minimal Safe Mode is probably your best bet, unless you need to access the internet (in which case, choose Safe Mode with Networking). This will load Windows with only the most crucial drivers and services running.
If you installed any new hardware recently, try uninstalling its drivers from Safe Mode. If you think a new application might be to blame, get rid of that too. BlueScreenView can help you look back through your most recent Blue Screens of Death to see the file that caused the problem, or any bug check strings and codes to Google.
You might even try running System Restore to try and get your PC back to the last known working configuration. Reboot the PC normally to see if it fixed the problem. If not, you can enter Safe Mode again, or try moving on to one of the next troubleshooting steps in this guide.
Roll Back a Problematic Windows Update
If you recently installed a Windows Update—or you think Windows may have done so in the background without you realizing—it may have caused a conflict that rendered your computer inoperable. It’s annoying, but thankfully, Windows does offer the option to roll back to the previous version, even if you can’t get into Windows itself.
Head back to the Troubleshoot > Advanced Options menu using the instructions above, then choose Uninstall Updates. Try uninstalling the latest Quality Update, or—if you recently tried to upgrade to a new major version of Windows 10—uninstall the latest Feature Update. If you’re lucky, this may get you back into Windows, at which point you can delay Windows updates until the kinks are worked out.
Check Your Hard Drive for Corruption
It’s possible some data on the drive is corrupt, preventing Windows from booting properly. Thankfully, Microsoft has a few tools that can attempt to fix the problem.
Head to the Troubleshoot > Advanced Options menu as described above and choose the Command Prompt. Type sfc /scannow and press Enter. Windows will check your drive for corruption and attempt to repair any problems.
You can also try the chkdsk C: /r command, which will do a broader search for file corruption and bad sectors. (If you have multiple drives, you may want to run wmic logicaldisk get volumename,name and replace the drive letter with the correct one from the resulting list.)
Repair a Busted Bootloader
Sometimes your Windows installation is fine, but the bootloader—the data that governs Windows’ boot process—is corrupted. This often happens if you clone your hard drive improperly, in which case you can try the cloning process again, making sure to clone the entire drive, not just the partition where Windows resides.
It can also happen if you try to dual-boot Linux or create new drive partitions and mess something up along the way. You’ll often get a message saying “Error loading operating system,” “Invalid partition table,” or “FATA: No bootable medium found! System halted.”
If you have a good backup, you can try to repair the bootloader using Windows’ built-in tools by going to Troubleshoot > Advanced Options as described above, then choosing Startup Repair. I wouldn’t attempt these steps unless you have your files backed up, as messing with partitions can always risk the loss of data. You can also run the Command Prompt from this menu and try running one of the following commands:
If that doesn’t work, repairing your bootloader may be more complicated due to newer EFI bootloaders—you can see instructions on doing so here—but it may be easier and faster to reinstall Windows from scratch and restore from your backup.
Test the Drive in Another PC and Pray
If all else fails and you don’t have a backup, take your hard drive out of your computer, connect it to a USB adapter, dock, or enclosure, and plug it into another known working PC. (Or, if you don’t have another PC, try booting from a Linux Live CD on your current machine.)
As long as the drive is still working—a big “if”—you’ll at least be able to copy your files onto an external drive for safekeeping before you reinstall Windows or send the PC in for repairs.