Does mac have BIOS?

to directly answer your question...

Current generation Mac's have an EFI or Extensible Firmware Interface, which is a later generation replacement to the very antiquated BIOS.

as far as reinstalling the OS... theres a simple built-in fix.. when you boot up and hear the "GONG"... simply hold down Command-R and be patient.. Mountain Lion restore will start, and allow you to install, via the internet.

Hope that helps!

You cannot boot into BIOS on a Mac, but you CAN boot from a CD/DVD/USB drive, by pressing and holding "Option" key right after you hear Mac turn-on chime (and then choose which device/CD you want to boot from) OR press and hold the "C" key on the keyboard (but you have to keep pressing it until you hear the computer start booting from the CD/DVD)). Good luck)

you can not...it's not like the pc notebook that you can press f12 or delete....

If your computer came with Lion/Mountain Lion pre-installed there is no CD/DVD. You use:

OS X (Lion/Mountain Lion)- About OS X Recovery

OS X Lion- About Lion Recovery

if your looking to get into the EFI settings, akin to getting into the BIOS settings, then there is no way..