Hello.
A few days ego I've made some changes to my computer (bought PSU, new hard drive Seagate 7200.10 320GB SATA, sound card, done some things with chassis) and I started to have some problems with system.
Computer started rebooting itself, I couldn't install downloaded stuff...

I use my old HDD - ST3120026AS Barracuda 7200.7 SATA 120GB for downloading and swap file.
I have noticed that on this HDD sometimes big files are different than source when coppied. Checksums are wrong, some bytes are changed. When I just copy ~1GB file I get a bad checksum for sure.

There is no such a problem on my new disk!

I hope I didn't damage it physically while modding of my computer.

Do you have any idea what could it be, how to diagnose/repair it?

My system: WinXP Prof SP2, Abit nf7-s, Athlon XP-M 2500+, 2x512MB RAM

Thanks in advance!

Could be bad RAM, bad HD, bad cables, just a bad connection, bad filesystem..

Test your RAM, test your hard drive. www.memtest.org and you can download dignostic tools from Seagate. Or just use www.ultimatebootcd.com

It may be that ur hard drive have been damaged or bad cables . may be ur hard disk not formatted properly or bad file system.Do one thing check all the connectivities properly and then restart comp again if it still wont work just format the hard drive.And if still after formatting it wont work it have been damaged