I Think i might have a similar problem to you even though mine is totally my fault,
I dont want my little sister messing around with things she dont know, so i though i would add security permission on the Hard drive, so i was in security and i highlited all user i think cant be sure as i cant access it now, and slected deny all rights then clicked apply, relising what i just did i cancel the action, and then did a systerm restore back to the point where i didnt do the permissions, but now i cant enter my hardrive or run system restore even when i am the administrater, so i need a way to change these permissions to allow me to get back into the hard drive even when it wont let me, please anyone right back as i am feeling a complete Tw*t cheers all help wanted.