Copying large (cached?) files freezes the whole system

Hi,

I've recently setup a simple test server using windows 2003.
It's setup as a domain controller, dns, dhcp, wins and routing & remote
access.

Hardware is really low budged: Celeron D, 512MB memory, Asrock mobo with
onboard video/sound/lan. One harddisk: Maxtor 200GB IDE.

Whenever I copy a directory with a total size of approx. 100MB or more:
The first time I copy it, there are no problems.
The second time, it takes a second or so before the copy action starts,
then, the progress bar will jump ahead and stop, jump ahead again, and stop,
every time maybe 10 or 20 percent, until the copy process is complete.
The time between the 'jumps' is a few seconds, it seems a bit random.

Whenever the progressbar stops, the whole computer stops responding.
I can move the mouse but none of the mouse clicks are being processed.
Also, the harddrive led is ON but I don't hear the drive doing anything; no
movement of the read/write head.
The cpu graph in the task manager freezes as well.

The moment the copy process continues, every mouse click or key entered
is fired and whatever I tried to do suddenly happens.

Tried another harddrive, newest bios, updated all drivers, no result.

Installed WinXP: no problems at all, copying files as smooth as it can get.
Reinstalled Server2003: problem is there again.

Also disabled the harddrive's write cache, no result.

Searched the MS knowledge base for possible causes but all I could find was
related to Terminal Server and I don't use that.

What can be going on here?


Thanks in advance!
Marcel