Hard drive diagnostic software

Can anyone suggest a good freeware/shareware to test a hard drive to see if it is physically ok (and if the data is correct too)? I run scandisk and defrag on occasion, but am wondering if there is something more thorough that won't harm the data while it tests. I seem to have had a few files that I download come out with CRC errors consistently and am wondering if the hard drives may be going wonky.

Thx,

 

Some manufacturer's tests are listed here:
http://www.pc-pages.co.uk/Hard_Drive/Hard_Drive_help_5.htm

This file corruption problem is widespread with XP (but maybe not exclusive to it). It has been mentioned many, many times in newsgroups. The problem seems to occur most with zip files.

Generally, it is explained away, but I think it is a real problem. It may be connection related. I think maybe half of zip files over 100 megs that I download are corrupted, even though they are fine on the other end. At this point, I think it has something to do with the frequency of IP renewal. Mine is renewed by my ISP every 3 hours, and I suspect it is during that time that the corruption occurs.

 

Well, in my case I'm still using win98 not XP, and the corruption problem has only been occurring over the past few months. Never had that problem before no matter what the file size. I think you're right when you say it's on the ISP side. They just won't admit to it.