if you have two stick of ram take one of them out and see if the error stops or changes...use open hardware monitor to watch your power supply voltage to see if it dropping. open the case and see that everything plugged in and the fans are moving.
1. Are you doing any particular activity when it crashes or is it random?
2. If it stays up long enough, can you assure you have all the latest OS video, audio, NIC and chipset drivers and system board BIOS?
3. Is the system clean inside and all fans running? Will it stay up if the case is wide open?
4. Can you boot from a live CD (Linux distribution for instance) and have it stay up ? If so, it's the OS (and if not look to hardware issues). If your system BIOS supports a diagnostic that may be a good place to start.
Acknowledged. I saw the BC code, but it does not rule out component overheating as a root cause of the failures, and booting from a live CD will take the OS out of the picture and point to hardware if it fails again. Standard troubleshooting is cheaper and less hassle than RMA'ing a part before all data are in.