CRC error with zip files

Ok, let's explain it simple.

1. My zip file is ok. I try it on 3 other computer without problem. Also, my DVD-ROM drive is ok because I try it over the net and on a USB key.

2. When I unzip this file (and a couple of others), there are always RANDOM CRC errors.

3. I also have problem with installation of some software, always with the CRC errors.

4. When I bought my computer, there where error EVERYWHERE and Dell techninal support made me change my BIOS and everything seems to be working but now it seems that others things goes bad.

Do you have any suggestion of things I might try before I waste like 5 hours trying to explain this simple fact to Dell technical support? I thinks it may be related to the fact that I have 8 GO in my computer (last time it was) but I'm not sure because I did the Dell test and it was ok!

Thanks a lot!

J-F