Hard drive failure, or bad computer?

I recently bought a Seagate half-terabyte drive (it was on sale). I promptly put it in my computer, formatted it ext3, and copied all my relevant data over to it. But soon, the drive was suffering from corruption that damaged both the filesystem and the files that survived. So, because I read that there was an ext3 bug in the 2.6.18 kernel (I was using 2.6.17, but didn't bother to check if there was a bug in that), I reformatted the drive in reiserfs and tried again. Immediately after copying the data onto it, the FS itself was suffering corruption. So, it sounds like a hardware problem.

I decided to run the Seagate boot-disk of diagnostics. It doesn't even detect the drive in my computer (!), so I put the drive in another computer, where the diagnostic tool sees it fine. In that other computer, the tests (both read and write, though no test that verifies data integrity of written data--I don't know why) all pass.

So, here's my question to you. Do you think this is likely to be the drive's fault? It has only exhibited problems in the one computer, but that computer has never given problems like this. Are there any other tests I should run? I suppose I could try copying a bunch of data onto the drive in the second computer, and seeing if it is corrupted--that would make it pretty clear it's the drive.

Thanks for all your help.