** I don't know much about nothing *grin* but this I do know ---
I have a GREAT gaming system at home.. with all the bells and whistles... I don't have my casino on her (as that would be an insult to my baby!)
She is spec'ed to the max and optimized to run high quality graphics, with memory beyond 'normal' and enough hard-drive space to create, save and back-up virtuall all of Nasa's secret stash... So what am I doing here (other than bragging about my lovely?)
Truth is, I have to run a FULL SIZE fan on her all the time, with her covers removed and not in her specially designed hole... Why? I dunno, but she overheats like an extinct meerkat on an deserted island.
As a matter of testing, I formatted and only installed the basic such as OS and the basic things like msnger. Checking only e-mails (what an isult!) and surfing a bit. Within 10 minutes without the industrial fan on her, she is bleeping again.. this suggests to me that it had NOTHING to do with the programs that is running, as some was saying.. and therefore I have not given much notice to the whole 'MGS' being responsible thing. *shrug*
May I suggest a few things to check - Other than MGS?
1) If the cpu setup was improperly installed, meaning too much paste and/or not fully seated can cause the cpu to overtemp and with a bios temp setting can reboot, if so reset.
2) Check your power supply (part of my problem was just that!)
3) Check the graphics card - if a hi-performence type maybe drawing too much wattage and it can cause a reboot. (Sounds daft, but tis true!)
4) You can download a free version of Sisoft Sandra from download.com and it will tell you if you are overclocked. (One of my systems had this problem where the bus speed was set too high
5) Clean your systems insides out with a air-spray... This usually settles my baby down for at least a while!!
6) GET A DESCENT FAN!!!!!
I know these things are probably totally irrelevant, but all in all, it just helps you to take better care of your machine anyway!
I realised that the most common problem is found to be clogged finns on the heat sink, and poorly mounted heat sinks follow a close second" - *smile*
If you manage to get the heat under control...but discover that you still have the reboot problem, it is almost certain that you have a memory timing problem, a defective memory chip, or a bad chip on the mainboard.
Well... what do I know anyway... riiight?

**