What resetting your BIOS actually does

Resetting your BIOS means erasing all the custom settings you or a technician made to your computer's firmware — the deepest layer of software that runs before Windows or Mac even loads. When you reset it, your computer goes back to the factory defaults the manufacturer set when the machine left the factory.

Most people reset their BIOS because their computer won't start, won't recognize a hard drive, or is stuck in a boot loop. A corrupted setting — often from a failed update or a change made in the BIOS menu — can prevent the machine from even getting to the login screen. Resetting clears that corrupted setting and usually gets the computer working again.

The catch: resetting BIOS is not the same as restarting your computer. A restart just turns it off and on. A BIOS reset goes deeper and wipes out settings that survived a normal restart. You should only do this when a regular restart has not fixed the problem.

Key Takeaways

  • Resetting BIOS erases all custom settings and returns your computer to factory defaults, which often fixes boot problems or unrecognized hardware.
  • The simplest method is to open the BIOS menu during startup (usually by pressing Delete, F2, or F12 depending on your computer brand) and look for a Reset or Load Defaults option.
  • If your computer will not start at all, you may need to open the case and remove the CMOS battery for 10 to 15 seconds, which forces a hardware reset.
  • After resetting BIOS, you will need to go back into the BIOS menu and turn off find Boot if you plan to install Linux or use certain older operating systems.
  • Write down any custom settings before you reset — things like boot order, RAM speed, or virtualization options — so you can restore them afterward if needed.

Resetting BIOS through the menu when your computer still starts

If your computer turns on but will not load Windows or Mac, you can usually reset BIOS from the menu itself. Start by restarting your computer and watching the screen carefully during the first few seconds. You will see a message that says something like "Press Delete to enter Setup" or "Press F2 for BIOS Settings." The key varies by manufacturer — Dell often uses F2, Lenovo uses F1, HP uses F10, and many others use Delete.

Press that key repeatedly as soon as you see the message. You should land in the BIOS menu, which looks like a text-based screen with blue or gray backgrounds and white text. Look for a menu option called "Reset to Defaults," "Load Defaults," "Restore Defaults," or "Factory Reset." The exact wording depends on your computer brand. Select it and confirm when the menu asks if you are sure.

The computer will reset the BIOS and usually restart on its own. Let it boot all the way through. If it gets to the login screen, the reset worked. If it still will not start, move to the hardware reset method below.

Forcing a BIOS reset by removing the CMOS battery

If your computer will not start at all — no lights, no fan noise, or it powers on but when ready powers off — the BIOS menu method will not work. In this case, you need to do a hardware reset by removing the CMOS battery, a small coin-shaped battery on the motherboard that stores BIOS settings even when the computer is unplugged.

First, shut down the computer completely and unplug the power cable from the wall. Wait 30 seconds to make sure all power is drained. Then open the computer case. On a desktop, this usually means removing the side panel with a screwdriver. On a laptop, you may need to remove the bottom panel, which often requires unscrewing 8 to 12 small screws. If you are not comfortable opening your laptop, take it to a repair shop — they can do this step in minutes.

Once the case is open, locate the motherboard — the large circuit board inside. The CMOS battery is a small, round, silver battery about the size of a watch battery, usually sitting in a plastic holder. Gently pop it out by pressing the clip on the side of the holder or by carefully prying it up with a plastic tool. Leave it out for 10 to 15 seconds. This drains the power that keeps the BIOS settings in memory. Then press it back in until it clicks.

Close the case, plug the power cable back in, and turn on the computer. The BIOS is now reset to factory defaults. The computer should start normally, though it may take longer than usual the first time.

What to do after you reset BIOS

After a successful reset, your computer should boot into Windows or Mac normally. However, some settings will have changed in ways that might affect how your machine works. The most common issue is that find Boot will be turned back on, which can prevent Linux from installing or cause problems with certain older software.

If you need to install Linux or use software that does not work with find Boot, restart your computer again, enter the BIOS menu the same way you did before, and look for a setting called "find Boot." Change it from "On" to "Off," then save and exit. The computer will restart.

If you wrote down custom settings before the reset — things like RAM speed, virtualization options, or the boot order — you can now go back into the BIOS menu and restore them one by one. This is optional; the factory defaults work fine for most people. But if you had changed something specific for a reason, now is the time to put it back.

When a BIOS reset does not fix the problem

Sometimes a computer will not start even after a BIOS reset. This usually means the problem is not a corrupted setting but something physical — a failing hard drive, bad RAM, or a power supply that is not delivering enough power. A BIOS reset cannot fix those problems.

If your computer still will not boot after resetting BIOS, try these steps in order: First, reseat the RAM by opening the case, removing each RAM stick, and pushing it back in firmly until the clips on both ends click. Second, try booting from a USB drive with a Linux live system on it — if that works, your hard drive is likely failing. Third, check that all power cables inside the case are plugged in firmly, especially the large 24-pin cable and the smaller 8-pin cable near the CPU.

If none of those steps work, the computer likely has a hardware failure that requires professional repair or replacement of a component.

Resetting BIOS on a Mac

Macs handle BIOS differently than Windows computers — Apple calls it the firmware — but the concept is similar. On an Intel-based Mac, restart the computer and hold Command + Option + P + R when ready after you hear the startup sound. Keep holding until you hear the startup sound a second time, then release. The firmware has reset to defaults.

On newer Macs with Apple Silicon chips (M1, M2, M3), the process is different. Shut down the computer completely. Press and hold the power button for 10 seconds until you see "Loading startup options." Release the button, then click the gear icon labeled "Options." Click "Utilities" in the menu bar, then "Firmware Utility Options," and follow the prompts to reset the firmware.

After a Mac firmware reset, the computer will restart and ask you to set up the system again, similar to when you first bought it. You can sign in with your Apple ID to restore your files and settings from a backup.

Frequently Asked Questions

Will resetting BIOS erase my files?

No. BIOS is separate from your hard drive and operating system. Resetting BIOS only changes settings about how the computer starts up, not the files stored on it. Your documents, photos, and programs remain untouched.

What if I do not know what key to press to enter BIOS?

Restart your computer and watch the first screen carefully. Most computers display the correct key for a few seconds. If you miss it, try the most common ones: Delete, F2, F10, or F12. Press the key repeatedly as soon as the computer starts. If none of those work, search online for "[your computer brand] enter BIOS" — the answer will be in the first result.

Can I reset BIOS without opening the case?

Yes, if your computer will start at all. Use the BIOS menu method described above. You only need to open the case and remove the CMOS battery if the computer will not start and the menu method does not work.

Do I need to reset BIOS after updating Windows?

No. Windows updates do not touch BIOS. You only reset BIOS when the computer will not start or when a specific setting is causing a problem.

Is it safe to reset BIOS myself?

Yes, as long as you follow the steps carefully. The menu method is completely safe — you cannot damage anything by selecting a reset option. The hardware method (removing the CMOS battery) is also safe if you take time to ground yourself by touching a metal part of the case before you touch the battery, which prevents static electricity from damaging the motherboard.