Don't forget the impending arrival (Hopefully) of DogseyOS! I'm hopeful it'll prove a great way to breathe new life into older hardware.

On the BIOS thing, the BIOS settings are entered by pressing one of the F<n> keys while the PC is booting up. You generally have to be quick to catch what key to press to enter the settings menus. Although there is generally an option to reset the settings to factory defaults, it does pay to be careful!