Files getting corrupted for no reason...

Certain files, especially zip files and ones that have been downloaded via Bittorrent, seem to be getting corrupted for no reason at all. This also applies to some JPG files as well. What could be causing this? The ratio of failure is pretty small so far, as I have thousands of files, but what's corrupting them in the first place? Are my hard drives failing?

this will occur most with files that rely on full data being intact, like compressed formats (jpg, zip). its less likely for text files or other things like that.

what's happening is you can't write good data anymore. you can still read, it seems, so i would get that shit off and move it.

You still have some options for recovering the drive, though, for backup use.

You say >>Are my hard drives failing?
does this mean it's happening on more than one? if so, it's possible you have a fucked up net connection. Try creating a large RAR and then hashing it.