So it happens I have some kind of a challenge with my 2TB HDD (Samsung HD204UI). I used Acronis to create two partitions, 32GB for the OS (Win2003 Enterprise) and the rest for data. Both partitions are aligned to the physical 4k sectors. The system runs fine as long as I don't have a certain amount of traffic on the HDD. When I run torrent 24/7, the system hangs after around 3 to 4 days, when I encode video to H.264/AVC it even hangs after around 12 hours. I suspect the HDD since this never happened before I used the 2TB HDD.

Even though:
system specs

edit: solved! The IPv6 Protocol Stack was at fault here and died regularely, killing the whole OS on its way down the drain . . .