I got a 1.5TB Caviar Green that shows up as only 465 GB (476961 MB) after a reinstall windows on another drive. Lots of data including email etc was backed up on the caviar that was also connected to the system. The motherboard was a gigabyte one, ill look up the exact one.
After XP was installed, it suddenly sees the caviar as only 465 GB with a 0K fat partition on it.
Now, I have been looking around and apparently Seagate users had a similar problem with some firmware “max size” setting.
Unfortunately, you jacked the drive when you left it connected while reinstalling windows on the other drive. You’re left with data recovery. You might be able to find some software that will restore the partition. Search Wikipeodia for data recovery.
Your Gigabyte BIOS (Award ?) is trying to grab about 2000 sectors at the top end of the drive in order to store a backup copy of itself for BIOS recovery purposes.
To do this, it hides the copy in a Host Protected Area (HPA).
Unfortunately, the BIOS code has a bug that causes it to miscalculate the size of the drive. In your case it reduces its capacity by 1TB, leaving you with only 500GB. A 1TB drive is cut down to 32MB or so.
You can restore the full native capacity of your drive using HDAT2:
