Can a computer work without BIOS?

If by “computer” you mean IBM compatible PC, then no, you must have the BIOS. Any of the common OS’s today have the equivalent of “the BIOS”, i.e., they have some embedded code in a non-volatile memory that has to run to boot the OS. It’s not just IBM compatible PC’s.

Why do we need to access BIOS before we install operating system?

BIOS provides the basic functions needed to boot your machine to allow your operating system to access your hardware. Your system probably provides a BIOS set-up menu, which is used to configure the BIOS. … AMI BIOS. Delete key during the POST (power on self test)