Pc keeps restarting

[LEGENDARYERIC]

My gaming pc keeps restarting when i do something in windowed mode (i.e. browsing the internet, checking steam and skype etc.). It does not do it directly, often it takes 10-15 min before it does. It never happens in fullscreen mode, I can play games for 5 hours just fine but after 15 minutes of browsing th internet it reestarts. I have reinstalled windows. What can cause this and how can I fix it? Can it be the RAM or the motherboard?

 

[McNeal]

Does the screen go blue then crash or straight to black.
If the screen goes straight to black your computer is overheating.

 

[LEGENDARYERIC]

Does the screen go blue then crash or straight to black.
If the screen goes straight to black your computer is overheating.

It goes straight to black so asuming that it is overheating, what cooler and what thermal paste should i use?

 

[McNeal]

Does the screen go blue then crash or straight to black.
If the screen goes straight to black your computer is overheating.

It goes straight to black so asuming that it is overheating, what cooler and what thermal paste should i use?

Be sure its a cooling issue. http://www.cpuid.com/downloads/hwmonitor/hwmonitor_1.28.zip
Download that and run it. Keep an eye on the cpu temperature. Report back the results along with your processor model.

 

[LEGENDARYERIC]

Does the screen go blue then crash or straight to black.
If the screen goes straight to black your computer is overheating.

It goes straight to black so asuming that it is overheating, what cooler and what thermal paste should i use?

Be sure its a cooling issue. http://www.cpuid.com/downloads/hwmonitor/hwmonitor_1.28.zip
Download that and run it. Keep an eye on the cpu temperature. Report back the results along with your processor model.

CPU temps: ~80C while gaming and ~60 while browsing
CPU model: intel i7 950 (I know its old but it works)

But as far as my limites experience goes shouldnt it reeboot more while gaming then?

 

[McNeal]

TCASE (Maximum Processor Temperature) 67.9°C
^ You processor is overheating. Either your fan isn't moving or your heat sink isn't connected anymore. If its a desktop simply open the side of the case and make sure everything is still moving properly. If your heat sink fell off clean it with isopropyl alcohol and reapply thermal paste.