i have ran into a problem like this a while back but was using clone cd and some how i lost my d: drive to i tried everything i could think of and in tha end i got it back but only after clean installing windows again sorry, this is tha only way i know of to fix a problem like this, but i suppose if u can find someone that is damn good at computers they might have a different solution.

p.s. i am suprized i could not fix it without formatting and clean installing windows again, i rarly have pc problems