Man I was duped into buying this HDD because it was cheap, now I know why. It is reported that the 7.11 Barracudas with the AD15 firmware has problems and retailers are getting up to a 30% return rate for these bricks.

Physically, your HDD is fine, so the freezing trick will NOT help. Symptons after an uncertain number of booting up your HDD will not be detected by BIOS (and possibly all your other SATA/PATA devices, even non-Seagate ones), or your BIOS reports it having 0GB capacity. Your data is still intact, however, something in the firmware is telling the BIOS that it is busy.

You can read some bits of it here:
http://forums.seagate.com/stx/search?submi...AS&page_size=10
Or search on on google for the ST3500320AS+BIOS

Simply due to the fact that Seagate doesn't want to acknowledge that this is a problem (because they don't want to fix it, not for free anyway) is enough for me to boycott Seagate products for EVER.