* Antec Sonata case w/ 500 watt PSU (Eath watts PSU)
* Intel DP55WG board
* Intel i5 quad core CPU
* Stock Intel CPU fan and thermal gel
* Crucial DDR3 memory (2GBx2)
* WD 500GB HDD
* Saphire ATI Radeon 4650HD PCI express video card (does not require additional power)
* Onboard audio and LAN
* Windows 7 x64
Randomly while using the computer it will reboot as if I hit the restart button. This will happen randomly when I watch a video (flash) for 30 minutes or listen to Zune for 20-30 minutes (although Zune ran for 24 hours all day yesterday with no problems) I can play Star Trek Online for about 20 minutes until it reboots or at times I can play for an hour or more with no problems. This has happen while editing photos as well in the Canon software.
I thought that it was blue screening however I don't see the blue screen so I set Windows to NOT reboot when a BSOD occurs however it still reboots which makes me feel a BSOD is not happening.
I ran memtest and it passed. I don't know if it's over heating or not or if this would even cause this to happen. I am not over clocking. I also have had this up and running for 2 days straight with no problems, I shut it off last night, turn it on this morning and in 10 minutes it reboots.
All drivers are updated, I even reinstalled Windows just to get a clean slate. I don't overclock or set any voltages and I'm not going in there to play with the settings, CMOS is set to default settings.
I ran memtest once, however I can run it as you suggested. I dont think it's heat due to the fact I ran it for 2 days straight have in run a couple of programs- then the next day I started it up and was looking through some photographs and in 10 minutes it rebooted.
I have another PSU that I believe will work and will try that as I know that PSU is working properly. I will also check out the HW monitor.