What BIOS Is and Why You Might Need It
BIOS (Basic Input/Output System) is the firmware that runs before your operating system loads. It controls hardware settings like boot order, fan speed, and security features. You access it by pressing a specific key during startup — before Windows, macOS, or Linux appears on screen.
Most people never need BIOS. But if you're troubleshooting hardware problems, changing which drive your computer boots from, enabling virtualization, or adjusting security settings, you'll need to get in. The key you press depends on your computer's manufacturer, and timing matters — you have only a few seconds after power-on.
Key Takeaways
- Press the correct key during the first few seconds after power-on, before the operating system loads — the key varies by manufacturer (usually Delete, F2, F10, or F12).
- Restart your computer and watch the startup screen for a message telling you which key to press; if you miss it, restart and try again.
- Different manufacturers use different keys: Dell and HP often use F2, Lenovo uses F2 or Enter, ASUS uses Delete, and Acer uses Delete or F2.
- If you're building a custom PC, the key depends on your motherboard manufacturer, which is printed on the motherboard itself or listed in its manual.
- Once inside BIOS, use arrow keys to navigate and Enter to select — do not change settings unless you know what they do, as incorrect changes can prevent your computer from starting.
Finding Your Computer's BIOS Key
The first step is identifying which key to press. Restart your computer and watch the screen carefully as it powers on. Most computers display a message during startup that says something like "Press Delete to enter Setup" or "Press F2 for BIOS Configuration." Write down that key.
If you don't see a message, or if it disappears too fast, check your computer's manual or the manufacturer's website. Search for your exact model number plus "BIOS key" or "enter setup." Common keys are Delete, F2, F10, F12, and Escape, but the exact key depends on who made your computer.
If you built your own PC, the key depends on your motherboard. Look at the motherboard itself — the manufacturer's name and model are printed on it — then search for that model plus "BIOS key." You can also check the motherboard manual if you still have it.
Restarting and Pressing the Key at the Right Time
Timing is critical. Power on your computer or restart it if it's already running. As soon as the screen lights up, begin pressing your BIOS key repeatedly — about once per second. Do not wait for the Windows or macOS logo to appear. You need to press the key during the very first few seconds, before the operating system starts loading.
If you see your normal desktop or login screen, you waited too long. Restart the computer and try again, pressing the key earlier this time. It usually takes a few attempts to get the timing right, especially on newer computers that boot very quickly.
Some computers require you to hold the key down rather than tap it. If tapping doesn't work after two or three restarts, try holding the key down for a few seconds instead. The BIOS setup screen will appear as a blue, gray, or black menu with white text — it looks very different from your normal operating system.
Navigating Inside BIOS
Once you're in BIOS, you'll see a menu with tabs or sections at the top and options listed below. Use your arrow keys to move up, down, left, and right. Press Enter to select an option or open a submenu. Press Escape to go back to the previous menu. Some BIOS versions also let you use Tab to move between sections.
Common sections include Main (showing your hardware), Boot (controlling which drive starts first), Security (password and TPM settings), and Advanced (CPU, RAM, and virtualization settings). Do not change anything unless you have a specific reason and understand what the setting does. Incorrect changes can prevent your computer from starting.
To exit BIOS without saving changes, look for an option that says "Exit Without Saving" or press Escape repeatedly until you return to the startup screen. To save your changes and restart, look for "Save and Exit" or "Exit and Save Changes." The exact wording varies by manufacturer.
BIOS Keys by Manufacturer
| Manufacturer | Common BIOS Keys |
|---|---|
| Dell | F2, Delete |
| HP / Hewlett-Packard | F2, Escape |
| Lenovo | F2, Enter, Fn + F2 |
| ASUS | Delete, F2 |
| Acer | Delete, F2 |
| MSI (Motherboards) | Delete |
| Gigabyte (Motherboards) | Delete, F2 |
| Intel (Motherboards) | Delete, F2 |
Troubleshooting When You Can't Get In
If you've tried the correct key multiple times and still can't enter BIOS, your computer may be booting too quickly. On newer machines with solid-state drives, the startup is so fast that the window to press the key is only one or two seconds. Try pressing the key as soon as you see any light or logo appear, even before text shows up.
If your computer has a BIOS password set, you'll be asked to enter it before accessing the menu. If you don't know the password, you may need to reset it. This usually requires opening the computer case and removing a small battery on the motherboard for a few minutes, or moving a jumper on the motherboard. Consult your computer's manual for the exact procedure.
Some laptops require you to hold a function key (Fn) while pressing the BIOS key. For example, Lenovo laptops sometimes need Fn + F2. Check your laptop's manual or support page if the standard key doesn't work.
Common BIOS Settings You Might Change
The most common reason people enter BIOS is to change the boot order — which drive the computer starts from. This is in the Boot section. You might do this to boot from a USB drive for troubleshooting or to install a new operating system. Use arrow keys to move a drive up or down in the list, then save and exit.
Other frequent changes include enabling virtualization (needed for virtual machines), adjusting fan speed (in the Advanced or Power section), or checking hardware information (in the Main section) to confirm your RAM and storage are recognized correctly. Again, only change settings if you know what they do.
Frequently Asked Questions
What's the difference between BIOS and UEFI?
UEFI is the newer version of BIOS. It does the same job but with a more modern design and better security features. Most computers made after 2010 use UEFI, though it's often still called "BIOS" in everyday conversation. You access UEFI the same way — by pressing a key during startup.
Can I damage my computer by changing BIOS settings?
Yes, incorrect changes can prevent your computer from starting. However, you can always restart and enter BIOS again to undo a change. If you accidentally change something, go back in, find the setting, and change it back. Most BIOS versions also have a "Load Defaults" or "Reset to Defaults" option that restores all original settings.
Why does my computer ask for a BIOS password?
A BIOS password prevents unauthorized people from changing hardware settings. If you set one and forgot it, you'll need to reset it by removing the CMOS battery on the motherboard or moving a jumper. This requires opening your computer case. Consult your manual for the exact location.
Do I need to enter BIOS to install Windows or another operating system?
Usually yes. You'll need to change the boot order so your computer starts from a USB drive or DVD containing the operating system installer. Enter BIOS, go to the Boot section, move the USB or DVD drive to the top of the list, save, and exit.
What if my keyboard doesn't work in BIOS?
Try a different USB port, or use a different keyboard if you have one. Some older BIOS versions don't recognize certain keyboard types. If you're using a wireless keyboard, plug in a wired one instead — wireless keyboards sometimes don't work in BIOS because drivers haven't loaded yet.