There isn’t a BIOS in the classic sense but there is a PRAM that occasionally needs a gentle prod. If the hardware is acting odd or booting isn’t happening, do this: (Assumes a Windows Keyboard)
1. Turn it off and unplug everything except power and keyboard.
2. Hold down <Alt> <Windows Key> <P> and <R> together and turn on the Mac.
3. You’ll hear the Wall-E startup sound as usual, then (keep those keys held down) the screen goes from white to black, and there will be a repeat of the jingle in 10-15 seconds.
4. Let go of the keys.
5. Let it boot up and then shut it down.
6. Time to boot it up again.
