This is my 2TB fileserver. I've already used 500Gigs in storage.

Asus p3b-f
Celeron 1.4ghz
512MB sdram pc133 *Memtest86 3.2 and 1.65+/Windows-Diag-MemTest/prime95/F@H stable.
Nvidia TNT 16MB video card
Relatek NIC Card
Highpoint RocketRaid 1740 raid card.
13Gig ide Fujitsu drive *O/S is installed on this drive*
Four 500GB Seagate SATA II drives in a hardware Raid 5
Simple cd-rom.
Seasonic 330watts Powersupply along with 950VA 540watt Battery backup.

Not sure, whats wrong or how I can troubleshoot it, but lately the machine locks up randomly. It only happens when someone tries uploading a file to the machine. The files can be anything from a simple .mpg to .exe, but the problem is that only certain files cause the machine to lock-up. I could have uploaded twenty .mpg files with no problems and then upload the next .mpg only to watch myself timed out on windows saying the host is no longer reachable and then I have to go physically reset the machine.

The problem can be recreated by uploading the same file again.
Work-around is to compress it then upload it to the machine.

Understand what I'm trying to say.

Yes, the machine is on a static ip, No the router is not the problem. I've hook up a Keyboard/Mouse/Monitor and when the next time it locks up, the machine does not respond to input.

I think its software problem and not hardware.

Someone help me troubleshoot this problem.