Playing games on my PC after a few minutes of running fine it goes really laggy and slow?

[Aidanmanc]

So ive been having this problem for about a year or so now, it all started when i got my new SSD and installed windows onto it, i noticed it didnt install properly because some of the updates would make the PC crash, so after numerous attempts i ended up not installing the updates and PC ran fine then i got Battlefield 3 and this was the first time it happened, as i was playing it, about 30-40 minutes into it the game just all of a sudden went really laggy and slow, like 1-2 frames per second, so i quite the game and my whole PC starts acting up being slow, you tube videos took forever to load and so on so i installed a fresh windows and that sorted it out but when i tried to play games it still happened so i did some searching around and found out it might be the registry so i had AVG tuneup and whenever it happened i went onto AVG tuneup and cleaned the registry and that seemed to fix the problem only for when i wanted to play games it would happen again. So i left it, didnt play games on my GAMING PC anymore because of the problem, left it for about a year until i kept getting bored and wanted to play some games, so i wanted to play Far Cry 4 and it just kept doing it over and over so i thought ill just install a clean windows 7 onto my SSD and i unplugged my other drives so the SSD was the only one. took a few attempts but finally got windows to install correctly and all the updates work fine now! but i still cannot play games, ive updated the graphics card drivers so everything is up to date! my friend said that his brother PC did the same thing and he has the same graphics card but his is a different make, mines and Asus and his is and Palit, but he said he put some new thermal paste on the GPU and it stopped doing it, so i did the same, used the same Thermal paste (not the best) and put some on the CPU aswell, and started to play again, but it didnt work so im stumped, i dont know if my graphics card has gone bad or something else has, can anyone help me diagnose this problem or know a solution for it, would be very appriciated!!!
Specs:
CPU : AMD 8320 8 core at 3.5GHz
Cooling: H100i
RAM: 8 GB DDR2
Motherboard: Gigabyte 970A DS3
Graphics : Asus GTX 660ti
Case: Corsair 600T
Power supply: OCZ 650W
C Drive/SSD: samsung 250GB 850 EVO
spare drives: 1T HHD/ 250GB HHD
Operating System: Windows 7

If ive missed anything just ask me!

 

[TurtleTom100]

Does it still lag on youtube?

have you tried using your mates graphics card? if so what happened? (if it still lagged card isnt going to be issue)

 

[Aidanmanc]

it Used to but when it happens now i restart the computer and the computer runs fine again, and nope i haven't yet!

 

[TurtleTom100]

it Used to but when it happens now i restart the computer and the computer runs fine again, and nope i haven't yet!

so it still lags then, i would recommend borrowing your mates graphics card see if it solves it if so buy a new graphics card if not will be in your pc. but you say you installed a clean install of windows and have run avg only other thing is try clearing bios but i doubt that will do anything. im no guru just have a fair bit of knowledge (i still ask questions on here myself lol.)

 

[Aidanmanc]

ill ask one of my mates and see if i can borrow his, cba buying a new graphics card though, got other stuff to pay for!

 

[TurtleTom100]

ill ask one of my mates and see if i can borrow his, cba buying a new graphics card though, got other stuff to pay for!

if it does solve it, you could always check on ebay as graphic cards are more hard wearing than other pc bits so used should be fine.

someone else may have another suggestion but that would be my first test, just try another card.