How to enter the BIOS or CMOS setup

Note: This document does not help if cannot enter BIOS or CMOS setup because of a password.

Because of the wide variety of computer and BIOS manufacturers over the evolution of computers, there are numerous ways to enter the BIOS or CMOS Setup. Below is a listing of the majority of these methods as well as other recommendations for entering the BIOS setup.

New computers

Computers manufactured in the last few years allow you to enter the setup using one of the five keys shown below during the boot. Typically it is one of the first three keys.

* F10 is also used for the boot menu. If F10 opens a boot menu, your setup key is likely F2.

You will know when to press this key when they see a message similar to the example below as the computer is booting. Some older computers may also display a flashing block to indicate when to press the F1 or F2 keys.

Press <F2> to enter BIOS setup

Tip: If your computer is a new computer and you are unsure of what key to press when the computer is booting, try pressing and holding one or more keys on the keyboard to cause a stuck key error. Once you get this error, you should have the option to continue or enter setup.

Once you have successfully entered the CMOS setup you should see a screen similar to the example below.

CMOS setup screen

Older computers

Unlike the computers of today, older computers (before 1995) had numerous different methods of entering the BIOS setup. Below is a listing of key sequences to press as the computer is booting to enter setup.

  • CTRL + ALT + ESC
  • CTRL + ALT + INS
  • CTRL + ALT + ENTER
  • CTRL + ALT + S
  • PAGE UP KEY
  • PAGE DOWN KEY

ACER BIOS

If your computer cannot boot or you want to restore the BIOS back to its bootable settings and your computer uses an ACER BIOS, press and hold the F10 key as you turn on the computer. While continuing to hold the F10 key, you should hear two beeps indicating that the settings are restored.

AMI BIOS

Older AMI BIOS could be restored back to bootable settings by pressing and holding the Insert key as the computer is booting.

BIOS or CMOS diskettes

Early 486, 386, and 286 computers required a floppy disk in order to enter the BIOS setup. These diskettes may be referred to as ICU, BBU, or SCU disks. Because these diskettes are unique to your computer manufacturer, you must obtain the diskettes from them. See the computer manufacturers list for contact information.

Early IBM computers

Some early IBM computers require you to press and hold both mouse buttons as the computer boots to enter the BIOS setup.

Other suggestions

Finally, if none of the above suggestions help get you into your CMOS setup you can cause a stuck key error, which causes the CMOS setup prompt to appear and remain until you press a key to continue. To do this press and hold any key on the keyboard and do not let go (you may get several beeps as you are doing this). Keep pressing the key until the computer stops booting and you have the option to enter setup.

Additional information