I am reasonably experienced building PC's and have a tough one I can't crack. I have a Gigabyte GA-K8NS Pro motherboard, an Antec 350 Watt PSU with "smart power", 1 GB RAM and an Athlon XP 64 3200+ processor. As you can see it's an older mobo but it's been really great. In any case, I had a striped RAID array on the integrated Silicon Images SATA controller and started to worry about total data loss if one of the drives should fail. I therefore purchased two new WD 500GB SATA drives and installed them mirrored on the same controller. The hard drives are SATA with a 3 GB/s transfer rate. I wiped my IDE hard drive with a new format and clean installed Win XP SP2, upgraded the bios, etc so it should have been a "new machine" type setup. Since that time, the computer has started "freezing" after between 30 minutes and 60 minutes of inactivity (sitting there doing nothing). I'll come back and find the mouse pointer frozen and the keyboard unresponsive, 3 finger salute has no impact. No errors or warnings in the XP event viewer, case and CPU temperature seem fine. I have a "backup" desktop which was a TigerDirect cheapie barebones kit. Ironically, it has also started freezing whenever I do a DVD rip -- after about 6 minutes of DVD reading the computer freezes and will not respond. Once again, no errors in the event viewer. Any suggestions? I'm more concerned about my Gigabyte-based machine as I have the larger investment in it, the other one is just a minor annoyance as otherwise it works fine. Thanks!