What BIOS is and why you might need to enter it

BIOS stands for Basic Input/Output System — it is the lowest-level software on your computer, running before Windows or Mac loads. It controls hardware settings like boot order, fan speed, and whether certain ports work. Most people never need to enter BIOS, but if you are troubleshooting a hardware problem, installing a new drive, or changing how your computer starts up, you will need to get in.

The catch is that BIOS looks different on every computer, and the window to enter it closes in seconds. You have to press a specific key during startup — usually Delete, F2, F10, or F12 — before the operating system takes over. If you miss it, you have to restart and try again.

Key Takeaways

  • You enter BIOS by restarting your computer and pressing a specific key during the first few seconds of startup, before Windows or Mac loads.
  • The key varies by manufacturer: Dell and HP often use F2 or Delete, Lenovo uses F2, ASUS uses Delete or F2, and you can check your computer's startup screen to see which key is listed.
  • If you miss the window, restart the computer and try again — there is no penalty for missing it.
  • Once inside BIOS, use only the arrow keys and Enter to navigate; the mouse does not work, and changing settings without knowing what they do can prevent your computer from starting.

Finding the correct key for your computer

The key you need depends on who made your computer. Restart your computer and watch the screen carefully during the first few seconds. Most computers display a message like "Press F2 to enter Setup" or "Press Delete to enter BIOS" — that message tells you exactly what to press.

If you cannot read the message in time, here are the most common keys by brand: Dell and HP usually use F2 or Delete; Lenovo uses F2; ASUS uses Delete or F2; Acer uses Delete or F2; MSI uses Delete; Gigabyte uses Delete. If your computer is a custom build or an older model, the manual that came with it will list the correct key. You can also search online for "[your computer model] enter BIOS" and find the answer in seconds.

Do not guess and press random keys during startup — you will not damage anything, but you may trigger other functions like boot menus or recovery mode. Stick to the key listed on your startup screen.

Restarting and timing your key press

Shut down your computer completely. Do not use sleep mode or hibernate — actually shut it down. Once it is off, press the power button to turn it back on.

Watch the screen from the moment it lights up. You will see the manufacturer's logo (Dell, HP, Lenovo, etc.) and then a message telling you which key to press. The window is usually two to five seconds long. Press the key repeatedly — do not hold it down, but tap it several times in quick succession. If you press too late, the operating system will start loading and you have missed your chance.

If you miss the window, do not panic. Let Windows or Mac finish loading, then shut down again and try once more. There is no limit to how many times you can restart and try.

Navigating BIOS once you are inside

Once you enter BIOS, you will see a menu with tabs or sections across the top or left side. The layout and colors vary widely — some BIOS screens look modern, others look like they are from 1995. Regardless of appearance, the controls are always the same: use the arrow keys on your keyboard to move between options, and press Enter to select or change a setting.

The mouse does not work in BIOS. Some newer computers have a touchpad or touch controls, but the arrow keys and Enter are always reliable. If you need to go back to a previous menu, look for an "Exit" or "Back" option and press Enter on it.

Do not change any settings unless you know exactly what they do. BIOS controls critical hardware functions, and changing the wrong setting can prevent your computer from starting. If you entered BIOS to fix a specific problem, search for that setting by name before you touch anything.

Common reasons to enter BIOS and where to find those settings

If you are installing a new hard drive or SSD, you may need to check that BIOS recognizes it. Look for a section called "Storage," "Drives," "SATA," or "Integrated Peripherals." You should see your new drive listed there. If it does not appear, the drive may not be fully seated in its slot — power off, reseat it, and restart.

If you need to boot from a USB drive or external device, look for "Boot Order," "Boot Sequence," or "Boot Priority." This section lists the order in which your computer checks for an operating system. Move your USB drive to the top of the list using the arrow keys and Enter, then save and exit. Your computer will now try to boot from the USB first.

If your computer is overheating, you can check fan speeds in a section called "Hardware Monitor," "System Health," or "Monitoring." This is read-only — you can see the temperatures and speeds but usually cannot change them from here. To adjust fan speed, look for "Fan Control" or "Thermal Management" in the main menu.

Saving your changes and exiting BIOS

After you make a change, BIOS does not save it automatically. Look for a "Save and Exit" option, usually at the bottom of the menu or in a dedicated section. Press Enter on it, and BIOS will ask you to confirm. Press Enter again to confirm, and your computer will restart with the new settings in place.

If you entered BIOS by accident and did not change anything, you can straightforward exit without saving. Look for "Exit Without Saving" or "Discard Changes and Exit." Your computer will restart with no changes made.

Some BIOS screens have a "Reset to Defaults" option. Do not use this unless you are certain you want to undo all custom settings — it will reset everything to factory defaults, which can affect boot order, fan speeds, and other configurations you may have set intentionally.

Troubleshooting if you cannot get into BIOS

If you press the correct key but nothing happens, try pressing it more rapidly or hold it down for a full second instead of tapping. Some computers are slow to respond, and the timing window is longer than it appears. Restart and try again.

If your keyboard does not respond during startup, the keyboard may not be powered yet. Wait a moment after you see the manufacturer's logo before you start pressing the key. If the keyboard still does not work, try a different USB port or a different keyboard if you have one available.

If you are on a laptop and the key does not work, check whether you need to hold the Function key (Fn) at the same time. Some laptops require Fn+F2 or Fn+Delete instead of the key alone. Check your laptop's manual or search online for the exact combination.

Frequently Asked Questions

Can I damage my computer by entering BIOS?

straightforward entering BIOS and looking around causes no damage. Changing settings without knowing what they do can prevent your computer from starting, but you can always restart and try again. If you get stuck, most BIOS menus have a "Reset to Defaults" option that restores the original settings.

What if I change a setting and my computer will not start?

Restart the computer and enter BIOS again. Find the setting you changed and revert it to its previous value, or use "Reset to Defaults" to restore all original settings. Save and exit. Your computer should start normally after that.

Do I need to enter BIOS to install Windows or Mac?

You may need to change the boot order so your computer boots from a USB drive or DVD instead of the hard drive. This requires entering BIOS and moving the USB or DVD to the top of the boot order list. Once Windows or Mac is installed, you can change the boot order back.

Is BIOS the same as UEFI?

UEFI is the modern version of BIOS and works the same way from a user perspective — you still restart, press a key during startup, and navigate with arrow keys. Newer computers use UEFI; older ones use traditional BIOS. The process for entering and using them is identical.

Why does my BIOS look completely different from what I see online?

Every manufacturer designs BIOS differently, and even the same manufacturer changes it between models and years. The layout, colors, and menu names vary widely. The controls are always arrow keys and Enter, but you may need to search for your specific computer model to find where a particular setting is located.