Pc restarts when playing games! :(

Sounds like you are overheating... Try to keep an eye out on your temps!

Check the inside for dust as that can make a huge difference in heat

hm i installed two fans. one fan as an intake and the other as exhaust. how to check the temp inside the rig?

i was downloaing a movie while i ws playing the game when i encountered this problem.

It does sound similar to overheating.

Are you over clocking any of the parts? (also check the bios isn't auto over clocking)

Check your power cables, make sure they are all firmly connected.

Get the program HWMonitor, that way you will be able to keep track of your temperatures and voltages.

You don't want the CPU to go over 75c under full load.

so should i put another fan?
will it increase the load on the psu?

is anything super hot? sometimes a chip is just made wrong and lets voltage jump across transistors, its not always heat to blame. ive had to underclock in the past to fix this issue. but if you think an area is getting bad air flow or is just overheating despite good air flow. do what makes sence to fix it. my biggest tips for air flow are.
-dont put your computer in a corner. it makes the hot air leaving your case go right back in. under desks is the worst.
-make the overall airflow in your case go from front to back. fans up front blow into the case and the ones in the back blow air out of the case.
-if you have a side duct for your processor use it. chuck a fan in there and let your cpu get nice and cool room temp air.
fans only use 5-20 watts just ignore their existance when calculating total wattage unless you have a lot.

I would say play the game again, not for extensive periods of time, and keep an eye of the temperatures using simple software such as HWMonitor to see what the temperatures are prior to shutdown (if it comes to that). Typically, temperatures will rise in gaming environments even if you are idle in them, so leaving the game on for a short while will generate results so long as you have a game running.

the first thing you need to do is make sure your graphics drivers are completely up to date.

the second thing you need to do is follow the recommendations already posted. download HWMonitor or Real Temp and check your temp under load. you'll do this by opening up your temp monitoring software, and then playing assasin's creed for a little while. (how long just kind of depends, but 1/2 hour should be more than enough) when you close the game, you'll have max values for your cpu and gpu temps recorded in your monitoring software.

post these numbers in this thread, and then people will be able to be more specific with their help. for now, there isn't enough information to determine what you need to do to fix your issue.

Best answer selected by briovaz.

i found the problem. my dust filters infront of air intake cooling fan were full of dust! after i cleaned the dust filter the pc didnt restart. i played about 12 hours straight for the past two days and the pc didnt restart. thankyou for your help people.