A new HDD could solve your issue. I do remember helping you out with this not long ago.
I bet you could still get it covered with Seagate. Just dont tell them that it was installed improperly. I am sure there are a 101+ ways to lie to them and get it replaced. Just tell them that after you installed Vista you got a lot of bad sectors and bad spots on the drive. Not much they can do if the drive is faulty.
