Strange PC Crashes, I need help and suggestions please!

Hi guys, im having annoying problems lately with my computer, after using my computer for a while usually 12/14hours of work and also for the past days it only crashes at around 4 am but during the day it runes smooth, the monitor would just go black and the pc restarts, sometimes it will restart with no problems, and other times, it does the double beep sound, and hangs on there. If I move my one stick of ram to another port on the mobo it would work, but the next day it would crash again, and i have to keep swapping the ports quite frequently.
Strangely it only happens when im on youtube or surfing on the net or if i leave my pc there on witout using it but, if im playing or running any applications like After Effects it will not crash.
I tried changing my ram with other ones that i had (3 sticks) nothing, my PSU is quite new.


My specs:
GPU: Nvidia GeForce GTS 450 (KFA2 edition)
CPU: AMD Phenom 955 X4 (3.2Ghz)
PSU: Corsair CX 500
Mother board: ASUS m4a78

Thank you in advance :)

YoYo155 said:

I would run Memtest86+, following this tutorial | RAM - Test with Memtest86+

Pay close attention to Part 3 of the tutorial if errors are found.

I have already did this, i have 2 sticks of RAM which are faulty, now im using a third one of mine, but i dont know this problem is killing me. Could it be PSU? MOBO? Overheating? CPU? GPU? thanks :)

Dude said:

AeTheCrash, welcome to sevenforums. Have a look in your event viewer and see if it shows the errors you see at around 4am.

Event Viewer - Open and Use in Windows 7

Thanks! I have ran this now, it says that all the shutdowns were from a source: Kernel Power

Dude said:

Have a look here too

Troubleshooting Steps for Windows 7

nothing seems to work! Can it be overheating? I havent cleaned dust off my pc for a long time, 2/3 years, i only used a hoover but it wont suck in all the dust

So on speccy it says that the GPU temp is: 61 °C but whats confusing me even more is the fact that 99.99% of the crashes occur when my pc isnt working so much, like on google chrome or even leaving my pc there without touching it