All your information is great... if he has a working PC
If he can't get past POST then he can't boot to anything, at all.
If it was past post and displaying an error of no valid boot media, then I could agree with your assumption that this can be sorted by starting from scratch.
But he can't boot to anything! Nothing. Nada. Nowt. His PC is effectively dead right now.
He must get the hardware fixed first.
However, if you have a way of installing XP and booting to it with out passing POST I am all ears
crabby