.
I'd not rely on a quick format with the Windows Disk Manager. May I assume you're using WinXP at this point ..?
With the drive connected directly to your system (NOT over USB),
1) I'd do a quick analysis and check SMART with the WD utility
2) then do a full detailed analysis (takes ~2-2.5 hours for a 2TB drive)
3) then do a full format with that WD analysis tool; it will also align sectors (again, ~2-2.5 for 2TB)
4) Does not hurt to check SMART again at that point & see if anything is changing dramatically; if so, that's a Bad Sign. Any changes should be VERY minor or not at all, that would indicate a healthy hardware situation ... which we suspect at this point, but would be nice to confirm before going through this all over again ...
THEN
5) I'd go into Win Disk Manager. You can cut the drive into 2 or 3 partitions; it can't hurt and there might be some benefit if something similar happens again. Chances are it won't make a difference, but it will not hurt you for that slim possibility that it could make a difference.
And, when you make those partitions (three max is good enough for the 1 TB, two enough for the 750 GB), do a full and real format w/ Disk Manager. You won't get a chance to do this again, hopefully ever, so spend a little time and do it right at the beginning.
Also, might want to do the very same steps 1) - 5) with the 750 GB before you rely on it. If it is not a Western Digital drive, you can still use the WD utility on it, as long as any Western Digital drive is detected on your system. I used that utility to analyze and format several 2 TB Samsung drives that way, a couple of them more than once.
You'll have done two different and full formats by the time you have your usable drive again ... if there's any errors at the disk/hardware level, they should turn up. Run SMART again and look for changes again when it's done. If no or minimal changes show up, you should have confidence that your drive is now "refurbished/recertified," so to speak.
Then, the other advice above about using it in a USB enclosure .. yeah. Pay close attention to disconnecting it properly, make sure your cable is quality & not loose, don't have your OS or other utilities doing stupid things like constantly accessing for no good reason.
You seem to be torrenting directly off this drive ..? Try to find another option. If you do that anyway, make sure the drive/enclosure are staying cool.
If you can place your system on an uninterruptable power supply, even a small one, that's a Good Plan. If there are small power variations (air conditioners, refrigerators, microwave ovens, hair dryers, etc.) in your current, those could cause write problems on your drives.
I lost several drives when lightening struck nearby and flickered the power for an instant. Surge suppressors (very powerful & professional quality ones) did nothing to help. Battery UPS keeps the current smooth through minor glitches like that and really helps to preserve the life of ALL electronics. I even use them on my best stereo componants when I can afford to. A 350V/550watt UPS is great, 750 W is better ... but even a 250 W will get you through little microsecond spikes and fails, even help you out for a couple minutes.
[ EDIT: @Slysoft -- RAID 0 does not mirror anything. It's for performance boost only. One drive fails, all is lost. RAID 1 is somewhat useful, RAID 5 is much more betterer. However, GoGeTa006 has already indicated that buying more drives at this point isn't an option. He's just going to have to risk it for a while, and take great care with what he has. With the 750 GB drive becoming available, you'll have a good manual back-up option for a while. Use the time to learn and plan how to prevent this in the future. ]
[ EDIT again: Huh. Sorry about that. "not as much as raid 0" threw me off. Careless/quick reading on my part. ]