Computer Restarts When Starting* Games & Sometimes Browsing

[igordos6]

Recently, I swapped my motherboard for an Asus M5A78l-M Plus/usb3 & my CPU for an AMD - FX 8300, since then, my computer started rebooting as soon as I logged into a game and sometimes randomly when browsing the internet (Including 2 tries of writing this thread). LoL, for example, as soon as I enter a game, my computer restarts, same thing with Counter-Strike: GO and Rainbow Six. I re-installed the graphics driver for my gpu (AMD R7 260x), worked fine for 2 days, then the problem came back today, seemingly happening more often, as mentioned above. Now I've been using my computer with the onboard graphics card as I tried before and no restarting occurred.
Any ideas of what could be causing this? Drivers? GPU? PSU?
Thanks for any help.


Specs:
GPU: AMD Radeon R7 260x
CPU: AMD FX 8300 Black Edition
Hard drive: Kingston SK300 240 GB
RAM: 8 GB DDR3

 

[R_1]

you swapped the motherboard and then reinstalled windows? yes? you should have re-installed windows with a hardware change of that magnitude. I'm surprised it even boots if you did not re-install.
what power supply do you have? how old is it?

 

[igordos6]

you swapped the motherboard and then reinstalled windows? yes? you should have re-installed windows with a hardware change of that magnitude. I'm surprised it even boots if you did not re-install.
what power supply do you have? how old is it?

Yes, I did re-install a few times. First I went to windows 10, but came back to windows 7 since a lot of the motherboard drivers weren't compatible with windows 10. My PSU is an Extream 650W FEX-65T28, and yes, it's a bit old, at least 2 years old. What's more likely to be causing the problem? The PSU or the GPU?

 

[R_1]

it could be both or either.
if the PSU cannot provide the power needed by the GPU the system will restart.
the GPU is a low powered unit.
you will need another system for testing, friend or sibling, swap power supplies and test the systems, you will test your system with a good known PSU and his system will test your PSU. if that yields no results swap the GPU's and test

 

[igordos6]

it could be both or either.
if the PSU cannot provide the power needed by the GPU the system will restart.
the GPU is a low powered unit.
you will need another system for testing, friend or sibling, swap power supplies and test the systems, you will test your system with a good known PSU and his system will test your PSU. if that yields no results swap the GPU's and test

Thanks man, will try that. The funny thing is that this never happened before, and the computer works just fine using the onboard graphics card. Do you think there's a possibility it has something to do with the GPU's drivers? Maybe incompatibility with the motherboard, don't know. Just really sad that I just bought all those new things and maybe I'll have to spend more money. =(