Ok, I have got 6 500gb hdds in my server, 4 on the sata ports on the motherboard, 1 IDE HDD and the last is on a via PCI sata controller PCI-VT6421A, it worked for about 2 days and then my whs server began locking up, I could not connect my PC's to it or my 360, the tray icon is grey, I coonect my monitor etc and the system has locked, I have to switch it off buy the mains. when I boot the pc up it works as normal for a while and then crashes again. I think it may have something to do with the addin PCI card but I cannot be sure. anyone got any suggestions. I am on removing the hdd from the pci controller and removing it to see what happens. Found out it maybe a driver problem crashing it as I have to use a XP driver for the card and Pluscom says they are not intending to release a 2003 driver.
HMG
That's one possibility. It could also be your power supply isn't strong enough (you didn't mention the wattage on it).