... is there something else i need to do?
Sounds like you need to beat your friend with a bat.
Really, though, we need more info. Did you format the drive, then install? install 'over the top' of your existing install?
how is your hard drive partitioned? (is it one big C drive, C & D, etc)
Seriously, I'd get your friend to get his ass over there and help you fix it, since he led you to do something you were apparently unfamiliar with.
Man, I hope you didn't lose a bunch of important data.