I bought last year a PC already assembled. It occasionally shuts down when starting a game. Since last month, it shuts down more often.
Here are the specs:
RAM: DDR3-1333 PC10666 2Gb
GPU: ATI Radeon HD 5850
CPU: i7 860 2.8Ghz
PSU: Xilence ATX 700W Gaming Edition
Mobo: Asus P7P55D
It seems to shut down when the GPU is used because it can happen when opening photos or videos in full screen. I don't know what to do at all because it's random. I can play 2 hours on Call of Duty without any problem, and the day after, it shuts down when launching the game.
Here are some data from the SpeedFan utility:
Sys Fan: 0 RPM
CPU0 Fan: 1875 RPM
Aux0 Fan: 778 RPM
CPU1 Fan: 0 RPM
Aux1 Fan: 0 RPM
Here are some data from the RealTemp utility:
It seems very high but the symptoms tend towards the GPU because I can do CPU intensive tasks without problems (compiling large applications, converting large videos).
In summer, it can be hot in the room, with temperatures between 25°C and 28°C, peaking at 30°C. I don't know if it's important. But the computer shut down several times in winter with room temperatures of 20°C.
When it shuts down, it does so completely and all the fans stop. 5 seconds later, it powers on by itself.
I can't seem to see a link between all those informations. Does anyone have an idea to help me?
Have you checked Event Viewer? See if it tells you anything around the time of the reboots.
It's possible the system is BSOD'ing and then automatically rebooting.
If so, you can disable this automatic reboot option by going to Control Panel --> System --> Advanced Tab --> Startup and Recovery --> Settings --> Uncheck Automatically Restart during System Failure.
The next time it does this, see if it BSODs instead.
If it does BSOD, first try running Memtest86+ (Download Here: http://www.memtest.org/#downiso) to check for errors in RAM. Let it run for at least 10 passes. If you do have errors reported from Memtest86+, check RAM settings (Timings and Voltage) in the BIOS to make sure they are set to the RAM manufacturers specs. If the settings are correct, try swapping the RAM into different DIMM slots on the motherboard. If this doesn't work, RMA the RAM.