Restart the computer
Immediately press one of these keys repeatedly during startup:
F2
F10
F12
Del
Esc
If your PC uses a Windows boot menu:
Open Settings
Go to System → Recovery
Under Advanced startup select Restart now
Select Troubleshoot → Advanced options → UEFI Firmware Settings → Restart
On some laptops/desktops:
Press and hold the power button for 10–15 seconds to turn off
Turn on and repeatedly press the BIOS key above during the first screen
If you see “Press [key] to enter Setup” during startup:
Press the shown key immediately
If none of the keys work:
Check your motherboard/laptop model’s manual or manufacturer website for the exact BIOS key