What BIOS is and how to get into it

BIOS stands for Basic Input/Output System — it is the software that runs on your computer before Windows, macOS, or Linux loads. Think of it as the control panel that sits between your hardware (your keyboard, hard drive, memory) and your operating system. You access BIOS by restarting your computer and pressing a specific key during the startup sequence, usually before the Windows or Apple logo appears.

The key you press depends on your computer's manufacturer. On most Dell, HP, and Lenovo machines, it is F2 or Delete. On Asus and MSI computers, it is often Delete or F2. On Apple computers, you hold Command + Option + P + R during startup to access firmware settings (Apple's equivalent). On some newer machines, especially those with Windows 11, you may need to restart into Windows settings first and choose "Restart now" under "Advanced startup options," then select "Troubleshoot" and "UEFI Firmware Settings."

The timing matters: you have only a few seconds after you press the power button and before the operating system starts loading. If you miss the window, your computer will boot normally and you will have to restart and try again.

Key Takeaways

  • BIOS is the low-level software that controls your hardware before your operating system loads, and you access it by pressing a specific key during startup — usually F2, Delete, or a key combination that varies by manufacturer.
  • The correct key depends on whether you have a Dell, HP, Lenovo, Asus, MSI, or Apple machine, and you must press it within a few seconds of powering on.
  • Common reasons to enter BIOS include changing the boot order, updating drivers, checking hardware temperatures, or enabling security features like find Boot.
  • BIOS changes can prevent your computer from starting if done incorrectly, so only change settings if you understand what they do or are following specific instructions.

Why you might need to access BIOS

Most people never need to enter BIOS. Your computer works fine without touching it. But there are specific situations where you do need to go in. If you are installing a new operating system or booting from a USB drive, you may need to change the boot order — the sequence in which your computer looks for a drive to start from. If your computer is overheating, you might check fan settings or monitor temperatures. If you are troubleshooting hardware problems, BIOS can show you whether your computer recognizes all your RAM or hard drives.

Some people also enter BIOS to enable security features like find Boot (which prevents unauthorized software from loading during startup) or to disable features they do not want running. Older machines sometimes need BIOS updates to fix bugs or improve performance, though this is less common now.

The difference between BIOS and UEFI

If you have a computer made in the last ten years, you probably have UEFI (Unified Extensible Firmware Interface) rather than traditional BIOS. UEFI does the same job — it initializes your hardware and hands control to your operating system — but it is newer, faster, and has a graphical interface instead of just text and menus. The process for accessing it is the same: restart and press the correct key during startup.

From a user's perspective, the difference does not matter much. Both are called "BIOS" colloquially, and both are accessed the same way. The main practical difference is that UEFI supports larger hard drives and boots faster, but you do not need to know this to use either one.

How to find the correct key for your machine

If you do not know which key to press, the fastest way is to look at your computer during startup. Most machines display a message like "Press F2 to enter Setup" or "Press Delete for BIOS" on the splash screen that appears before Windows loads. This message is usually visible for only a few seconds, so you may need to restart a few times to catch it and read it clearly.

If you cannot see the message, search online for your computer's model number plus "BIOS key" or "how to enter BIOS." Your model number is usually printed on the bottom or back of your machine, or you can find it in Windows by right-clicking "This PC" and selecting "Properties." Once you have the model number, a quick search will tell you exactly which key to press.

What to do if you cannot get into BIOS

If you press the key and nothing happens, you may have pressed it too late or too early. Try restarting and pressing it repeatedly as soon as you see the manufacturer's logo, rather than waiting for a specific moment. Some computers require you to hold the key down rather than tap it.

On newer Windows machines, if the traditional key does not work, try restarting into Windows settings instead. Go to Settings, then "System," then "Recovery," then "Advanced startup," and click "Restart now." When your computer restarts, you will see a menu with the option "Troubleshoot." Select that, then "Advanced options," then "UEFI Firmware Settings." This route bypasses the timing issue entirely.

If you are on a work or school computer, BIOS access may be locked by your IT department, and you will not be able to enter it at all. In that case, contact your IT support team if you need something changed.

Common BIOS settings and what they do

Once you are in BIOS, you will see menus with names like "Main," "Advanced," "Boot," "Security," and "Exit." The "Boot" menu is where you change the order in which your computer looks for a drive to start from — useful if you want to boot from a USB drive or external hard drive. The "Main" menu usually shows your hardware: how much RAM you have, what hard drives are installed, and sometimes the current date and time.

The "Security" menu is where you enable or disable features like find Boot, which prevents unsigned software from loading during startup. The "Advanced" menu contains settings for power management, virtualization, and other features most people never need to touch. If you are not sure what a setting does, do not change it. Changing the wrong setting can prevent your computer from starting.

When to ask for help before making changes

If you are in BIOS because you are following instructions from a technician, a repair guide, or a specific tutorial, follow those instructions exactly and change only what they tell you to change. If you are exploring on your own and you see a setting you do not recognize, leave it alone. BIOS changes are permanent until you change them back, and some changes can make your computer unbootable.

If you need to make a change but you are not sure whether it is safe, take a photo of the current settings with your phone before you change anything. That way, if something goes wrong, you can restart and change it back to what it was. If your computer will not start after a BIOS change, most machines have a way to reset BIOS to factory defaults — usually a jumper on the motherboard or a battery you can remove briefly — but this is more involved than changing a setting back.

Frequently Asked Questions

Is it dangerous to go into BIOS?

Going into BIOS and looking around is safe — you can read settings without risk. Changing settings can cause problems if you change the wrong thing, but if you only change what you intend to change and leave everything else alone, the risk is low. If something goes wrong, you can usually restart and change it back.

Will entering BIOS delete my files?

No. BIOS runs before your operating system loads, so it has no access to your files. Entering BIOS, looking around, and exiting will not affect anything on your hard drive. Only if you change a setting that affects how your hard drive is recognized could you run into problems, and even then your files would still be there — your computer just would not be able to read them until you fix the setting.

Can I change my password in BIOS?

Some computers allow you to set a BIOS password, which requires you to enter a password before BIOS will load. This is a security feature, but it is not the same as your Windows or Mac password. If you set a BIOS password and forget it, you will need to reset BIOS to factory defaults, which usually requires opening your computer or removing a battery — a job for a technician.

What if my computer is a Mac?

Apple calls its firmware "Firmware" or "Startup Security Utility" rather than BIOS, but it serves the same purpose. On Intel Macs, restart and hold Command + Option + P + R to access it. On newer Apple Silicon Macs (M1, M2, M3), restart and hold the power button until you see "Loading startup options," then select "Options" and "Continue." The settings are different from Windows BIOS, but the idea is the same.

Do I need to update my BIOS?

Most people do not. BIOS updates are usually only necessary if you are having a specific hardware problem, your manufacturer has released a security patch, or you are installing new hardware that requires it. If you are not sure whether you need an update, you do not need one. Check your manufacturer's support page for your specific model if you want to know whether an update is available.