http://support.wdc.com/product/download.asp?groupid=504&lang=en
And use it to test your HDD.
If the drive doesn't show up with this software it's not properly installed in the computer. ;)
Of course normal testing with this utility requires you to test the drive int he original computer first and then if it fails that test remove it fit it to another system and retest.
If it fails the second test the drive has gone to [b]Silicon Heaven[/b] but if it passes the second test the M'Board, Power Supply or Data Lead in the original computer is faulty and needs replacing. ;)
Col