[Solved] My monitor blinks with mixed and Checkered colors and system hangs

Hello,
my monitor blinks with mixed and Checkered (plaid) colors and system hangs for a few seconds then after a few seconds it happens again
what's the problem?
my system specifications is:
M.B: Asus P8P67
CPU: Corei7 2600k
V.G.A: xfx 5970 black edition 2g
power: thermaltake 600w
ram: 4g+4g 1600 apacer gold

mouse pointer will work and right click options are also available after blink
but launcher is absent too

thanks for the reply my vga is for 3 years ago and yes i have overclocked bothe cpu and vga but i'm runing the system as default optimize but there is still the problrm

How did you overclock your cpu?
By multi or the B-clk?

and i was ocerclocked the gpu too and now it's set to default and i was using the overvolt tool too

i can test a more powerfull power but i was using the 600w and i gived 200w to cpu by bios in the time iwas overclocking it and that was working good but now cpu spends just 120 w power

when i don't use the overvolt tool in amd catalyst center it won't show my gpu heat

is ADA64 a hardware?

thanks and can you give me the link for ADA i can't find it

thanks a lot i'll use this softwares to test hardwares but how i can be sure the problem is from the hardware (blue screen?

is there possible a virus can do this?

Give us the voltage readings that Aida says, also do what recon says and run those programs, keep an eye on temps.