Problem when playing 3d games

[mistatic]

So whenever i play 3d games random lines start coming out of the graphics and random specs and it flashes. After a while of playing the computer then freezes and shuts down. If you could help me with this problem it would be much appreciated :slurp:

Here is my specs:
ADM Athlon 64 x2 Dual Core Processor 4600+
2048mb Ram
256mb GeForce 7900 GT
Realtek HD audio output

~MisTaTiC~

 

[JMMD]

Sounds like either a video card going bad or overheating. Have you checked the temps of the CPU and the GPU?

 

[mistatic]

sorry to sound like a noob but how do i check this?

 

[tipstir]

Check the PSU (power supply unit)
Clean out all dust out of the CPU heatsink fan and all fans plus the PSU.
Try chaning out the PSU with another one higher that what you're using.
I would do that first before replacing Video card.