Unseize HDD

Defcon had the same problem a while back, stuck it in the freezer for 24 hours and it started working for him again.
http://geeksaresexy.blogspot.com/2006/01/freeze-your-hard-drive-to-recover-data.html
Not saying it will work, or even to try it but it might be worth a shot.
Its normally heat that causes problems for drives so logically freezing the drive might temporarily fix it again.
Just remember to stick it in a ZipLock Bag first.