What BIOS is and why you might need to enter it
BIOS stands for Basic Input/Output System — it is the firmware that runs on your computer before Windows, Mac OS, or Linux even starts. Think of it as the layer between your hardware (your motherboard, hard drive, RAM) and your operating system. Most of the time you never see it. But if you need to change boot order, disable a hardware component, check your hard drive health, or adjust fan speeds, you have to go into BIOS to do it.
BIOS is not the same as your operating system settings. You cannot reach it from Windows or Mac settings menus. You have to interrupt the boot process and enter it directly, which means restarting your computer and pressing a specific key at exactly the right moment.
On older computers, BIOS was the only firmware layer. On newer computers (especially those made after 2010), you may have UEFI instead, which is a newer version that works the same way from a user perspective but has more features. The steps to enter it are identical.
Key Takeaways
- You enter BIOS by restarting your computer and pressing a specific key during startup — usually Delete, F2, F10, or F12, depending on your manufacturer.
- The key you need appears on your screen for only a few seconds during boot, so you may need to restart a few times to catch the timing.
- BIOS controls hardware settings like boot order, hard drive detection, and fan speed — not software settings like passwords or display resolution.
- Changes you make in BIOS take effect when ready and persist until you change them again, so write down what you change in case you need to undo it.
- If you enter BIOS by accident and do not know what you are looking at, press Escape or select Exit Without Saving to leave without changing anything.
Finding the correct key for your computer
The key you press to enter BIOS depends on who made your motherboard or computer. During startup, your computer displays a message for a few seconds that says something like "Press Delete to enter Setup" or "Press F2 for BIOS." That message tells you the exact key to use.
If you miss the message, here are the most common keys by manufacturer:
| Manufacturer | Key to Press |
|---|---|
| Dell | F2 or Delete |
| HP / Compaq | F10 or Escape |
| Lenovo | F1, F2, or Enter (depends on model) |
| ASUS | Delete or F2 |
| Acer | Delete or F2 |
| MSI | Delete |
| Gigabyte | Delete |
| Apple Mac | Command + R (Recovery mode, not traditional BIOS) |
If you built your own computer, check the motherboard manual or the manufacturer's website. The manual came with your motherboard or is available as a PDF read using your motherboard model number.
The step-by-step process to enter BIOS
Restart your computer completely. Do not use sleep mode or hibernate — shut it down fully, wait a few seconds, then turn it back on.
As soon as the computer powers on, begin pressing your BIOS key repeatedly — about once per second. You are aiming to press it during the few seconds before your operating system starts loading. If you see the Windows or Mac logo appear, you waited too long and will need to restart again.
When you press the key at the right moment, your screen will change to a blue or gray menu with white text. This is BIOS. The exact layout and colors vary by manufacturer, but the menu structure is similar across all of them.
If you enter BIOS by accident or change your mind, look for an option that says "Exit Without Saving" or "Discard Changes and Exit." Press Enter to select it. Your computer will restart and boot normally.
What you see inside BIOS and where to find common settings
BIOS menus are organized by tabs or categories. The exact names vary, but here are the sections you will encounter most often:
Main or System Information: Shows your CPU, RAM, hard drive model, and BIOS version. You usually cannot change anything here — it is read-only information.
Boot: Controls the order in which your computer tries to start from different devices (hard drive, USB drive, CD drive, network). If you need to boot from a USB drive to install Windows or run a repair tool, you change the boot order here.
Advanced: Contains settings for CPU, RAM, and power management. Most users never need to touch this section. Changing settings here without knowing what you are doing can make your computer unstable.
Security: Where you set a BIOS password (separate from your Windows password) or enable find Boot. find Boot is a security feature that prevents unsigned software from running at startup.
Save and Exit: Where you save your changes and restart the computer. If you made changes and want to keep them, you must select this option — straightforward restarting without saving will discard your changes.
Common reasons to enter BIOS and what to change
Your computer will not start from a USB drive: Go to the Boot tab and move USB or "Removable Devices" to the top of the boot order. Save and exit, then insert your USB drive and restart.
Your hard drive is not showing up: Go to the Main tab and check if the drive is listed. If it is not, the drive may be failing or disconnected. If it is listed but Windows does not see it, you may need to initialize it in Windows Disk Management instead.
Your computer is overheating: Go to the Advanced or Power tab and look for fan speed settings. You can set fans to run faster, though this will make your computer louder. If fans are already at maximum and the computer is still hot, the problem is usually dust buildup or a failing fan, not a BIOS setting.
You want to disable a hardware component: Go to the Advanced or Integrated Peripherals tab. You can disable built-in devices like the webcam, Bluetooth, or audio. This is useful if a device is broken and you want to prevent Windows from trying to use it.
What not to change in BIOS
BIOS settings control hardware directly. Changing the wrong setting can make your computer unstable, prevent it from starting, or cause data loss. If you do not know what a setting does, do not change it.
Do not change CPU voltage, clock speed, or multiplier settings unless you are intentionally overclocking and understand the risks. Do not disable your hard drive or RAM. Do not change memory timings or frequency unless you know what you are doing.
If you make a change and your computer stops working, restart and go back into BIOS. Select "Load Defaults" or "Reset to Factory Settings" (the exact name varies). This will undo all your changes and return BIOS to its original state. Then restart normally.
Frequently Asked Questions
What is the difference between BIOS and UEFI?
UEFI is the newer version of BIOS. They do the same job, but UEFI supports larger hard drives, boots faster, and has a graphical interface instead of text-only menus. On newer computers, you have UEFI. The steps to enter it are the same — press the same key during startup.
Can I change my BIOS password if I forgot it?
If you set a BIOS password and forgot it, you cannot reset it from within BIOS. You will need to either contact the manufacturer with proof of ownership, or open the computer case and remove the CMOS battery for a few minutes to reset BIOS to factory defaults. This is a hardware-level reset and will erase all your BIOS settings.
Is it safe to update BIOS?
BIOS updates fix bugs and add support for new hardware. They are usually safe, but if the update fails or your computer loses power during the update, your computer may not start. Only update BIOS if your computer is plugged into a power outlet and you have a stable power supply. Do not update BIOS just to update it — only update if you have a specific reason.
Why does my computer ask me to press a key during startup but I do not want to enter BIOS?
Your computer is probably asking you to press a key to choose a boot device. If you do not press anything, it will boot normally from your hard drive after a few seconds. If you want to stop seeing this message, go into BIOS and disable "Boot Menu" or "F12 Boot Menu" in the Boot tab.
Can I access BIOS from Windows without restarting?
On newer Windows computers (Windows 10 and later), you can go to Settings, System, Recovery, and select "Restart now" under Advanced Startup. This will give you a menu to enter UEFI without pressing a key during boot. On older computers or Macs, you must restart and press the key during startup.