PC FPS Destroyed

[Icedlightning]

OK,So I have this rig and it's taken a turn for the worse which is driving me crazy as i can't figure out whats wrong.
I've had this computer for just two years now and till recently its never given me a problem.
One day outta the blue,the fps in all games just starts high for about a second,then drop and settles at about fifteen permanently.(Team Fortress 2,League of legends,Dragon Age 2,Sims)

I did see my nephew flip the power switch in the back when it was on and running at about the time it happened,though i have no idea if it did anything.

My specs:
AMD Phenom 9550 Quad-Core Processor
GEforce 9600 GT Graphics Card
4 Gigs DDR3 Ram
Windows 7 Ultimate Edition 64-bit

 

[Icedlightning]

Any help would be much appreciated,thanks in advance.

 

[ross_mitchell]

Thats quite a weak processor for a ddr3 board.

Are you certain that its a 9550 and not a 955.

 

[Icedlightning]

Yes,I'm sure its a 9550.
I'm sorry i'm new to this,anything i can provide that would help you help me i'll do in a heartbeat,i'm not sure if you needed more specs or such.

 

[Supernova1138]

Download HWMonitor and look and after exiting out of a game look at your CPU and GPU high temps. If one or both of them are really high then your computer is throttling itself to prevent damage due to excessive heat. If it is a heat issue, use canned compressed air to clean the dust off of all air intakes and fans. Also verify that the fans are working properly, if your CPU or GPU fan isn't spinning that would also cause overheating issues.

The other main possibility is that your PSU cannot produce enough power to run your components at full load, and they are running at lower clocks because of this. Best way to test this would be to try a different power supply. However, if a PSU does not have enough power it will usually shut down rather than cause components to throttle. Also check to make sure your Windows power profile is set to performance. If it is set to power saving mode, then your CPU and GPU are probably not running at maximum capacity in order to save power.