I have a Toshiba Satellite R20, and it's windows installation is corrupted. I wanna get into the bios but have no idea how. I just wanna boot from Cd, how do i make it do that? Btw, i only get to the screen telling me windows files are missing.

on a Toshiba, you can use PF12 to select a one-time boot device,
but the BIOS is accessed via F2

thank u my friend