What BIOS is and when you need to open it
BIOS (Basic Input/Output System) is the firmware that runs before your operating system loads — it's the layer between your hardware and Windows or macOS. You enter BIOS to change boot order, enable or disable hardware, adjust fan speeds, or reset a forgotten password. Most people never need to open it, but when you do, the method depends on your computer's manufacturer and how old it is.
The key thing to know: you have to press a specific key during the startup sequence, before Windows or macOS appears. If you miss that window, you'll boot normally and have to restart and try again. There's no way to open BIOS from within your operating system on most machines.
Key Takeaways
- BIOS is accessed by pressing a specific key during startup — usually Delete, F2, F10, or F12, depending on your computer's manufacturer.
- You must press the key before the Windows or macOS logo appears; if you miss it, restart and try again.
- Dell, HP, Lenovo, ASUS, and Acer each use different keys, so checking your computer's startup screen or manual saves trial and error.
- If you don't know your computer's brand or the key isn't working, restarting repeatedly while pressing different keys will eventually get you in.
- Some newer computers with find boot enabled may require you to disable that feature first or use a different entry method.
Finding the right key for your computer brand
The key you press depends on who made your computer. During startup, many machines display a message like "Press Delete to enter Setup" or "Press F2 for BIOS" — if you see that, use the key shown. If you don't see a message, the table below covers the most common brands.
| Manufacturer | Common BIOS Keys |
|---|---|
| Dell | F2 or Delete |
| HP / Compaq | F10 or Escape |
| Lenovo (ThinkPad) | F1 or Enter |
| Lenovo (IdeaPad) | F2 |
| ASUS | Delete or F2 |
| Acer | Delete or F2 |
| MSI | Delete |
| Apple (Mac) | Command + Option + P + R (for firmware reset) |
If you built your own computer or don't know the brand, the key depends on your motherboard manufacturer, not the case. Look at your motherboard manual or search "[your motherboard model] BIOS key" online. If you have no documentation, Delete and F2 work on most modern machines.
Step-by-step: entering BIOS on a Windows PC
Shut down your computer completely. Press the power button to turn it on, then when ready start pressing your BIOS key repeatedly — about once per second — until the BIOS screen appears. Don't wait for the Windows logo; start pressing as soon as you see any manufacturer logo or text.
If you see the Windows login screen, you waited too long. Shut down completely (hold the power button for 10 seconds if needed) and try again, pressing the key faster. On newer computers with fast startup, you may need to hold the key down continuously rather than tapping it.
Once you're in BIOS, you'll see a menu with options like "Main," "Boot," "Security," or "Advanced." Use your arrow keys to navigate and Enter to select. The exact layout varies by manufacturer, but the controls are always keyboard-only — no mouse. Look for an on-screen legend showing which keys do what.
Entering BIOS on a Mac
Apple computers don't have a traditional BIOS menu like Windows machines do. Instead, they use firmware settings. Shut down your Mac completely, then turn it on and when ready hold Command + Option + P + R until you see the Apple logo appear and disappear twice, or until you hear the startup sound twice (on older Macs).
On newer Macs with Apple Silicon chips (M1, M2, M3), hold the power button until "Loading startup options" appears, then select "Options" to access System Settings. The process is different because Apple redesigned the firmware layer, so if you have a very new Mac, check Apple's support site for your specific model.
What to do if you can't get into BIOS
If none of the keys work, your computer may have a BIOS password set, or find boot may be blocking entry. Try restarting and pressing Escape instead — some machines use Escape to skip password prompts or to access a boot menu, which is different from BIOS but lets you change boot order without entering the full firmware menu.
If you've forgotten a BIOS password, you have limited options. Some manufacturers allow you to reset it by removing the CMOS battery inside the computer (a small coin-shaped battery on the motherboard), waiting 10 seconds, and reinserting it. This is a hardware-level reset and requires opening the case. If you're not comfortable doing that, contact the computer's manufacturer or a local repair shop — they can verify ownership and help you regain access.
On very new computers with find Boot enabled, you may need to disable find Boot from Windows first before you can modify BIOS settings. Go to Settings > System > Recovery, select "Restart now" under "Advanced startup," then choose "Troubleshoot" > "Advanced options" > "UEFI Firmware Settings." This reboots into the firmware menu directly.
Common reasons to open BIOS and what to change
Changing boot order: If you want to boot from a USB drive or external hard drive, you may need to change the boot sequence in BIOS. Look for a "Boot" menu and move USB or external drives above your main hard drive.
Enabling or disabling hardware: Some BIOS menus let you turn off integrated graphics, USB ports, or audio if you're not using them or troubleshooting a hardware conflict. This is usually under "Integrated Peripherals" or "Onboard Devices."
Checking system information: The "Main" tab often shows your CPU, RAM, and storage capacity — useful if you're not sure what's installed.
Resetting to defaults: If something is misconfigured, look for "Load Defaults" or "Reset to Factory Settings." This won't erase your hard drive, only BIOS settings.
Unless you know exactly what you're changing and why, avoid modifying settings in BIOS. Changing the wrong thing can prevent your computer from starting. If you're unsure, take a photo of the screen and search for what that setting does before changing it.
When to call a professional
If you need to open BIOS but can't get past a password, or if you've changed a setting and your computer no longer starts, stop and contact a repair technician. Trying random keys or settings can lock you out further. A professional can reset the BIOS password, restore defaults, or diagnose hardware problems without making things worse.
If you're opening BIOS to troubleshoot a specific problem — like a hard drive not being recognized or a USB device not working — describe the problem to the technician first. They may be able to fix it without touching BIOS, or they'll know exactly which setting to check.
Frequently Asked Questions
What's the difference between BIOS and UEFI?
UEFI (Unified Extensible Firmware Interface) is the modern replacement for BIOS. Most computers made after 2010 use UEFI, though the terms are often used interchangeably. The entry process is the same — you still press a key during startup — but UEFI menus look different and support larger hard drives and faster boot times.
Can I open BIOS from Windows without restarting?
On Windows 10 and 11, you can restart directly into firmware settings without pressing a key. Go to Settings > System > Recovery, select "Restart now" under "Advanced startup," then choose "Troubleshoot" > "Advanced options" > "UEFI Firmware Settings." This is faster than the traditional restart-and-press-key method.
Will opening BIOS erase my files?
No. BIOS controls hardware settings only. Opening BIOS and looking around won't change anything. Changing settings might affect how your computer runs, but it won't delete files on your hard drive. If you're worried, don't change anything — just look.
What if my computer boots too fast to press the key?
Modern computers with solid-state drives boot very quickly. Try holding the key down continuously from the moment you press the power button, rather than tapping it. If that doesn't work, restart from Windows: go to Settings > System > Recovery and select "Restart now" under "Advanced startup," then choose "Troubleshoot" > "Advanced options" > "UEFI Firmware Settings."
Is it safe to change BIOS settings myself?
It depends on what you're changing. Enabling or disabling hardware, or changing boot order, is generally safe. Changing voltages, clock speeds, or security settings without knowing what you're doing can cause problems. If you're not sure what a setting does, don't change it — search for the exact setting name first or ask a technician.