Nvidia Geforce 8800GTS 640MB Flicker

OK people I'm getting crazy ,

In bought a PNY 880GTS 640MB about 2 months ago, i installed it , put the latest drivers at that moment in nvidia's page and all were running smooth. Then i installed an application called foxOne that came with my motherboard , is a kind of dynamic overclocking , temperature measuring utility. After that i stat to get some rare flicker in movies and in games. But after some tests i uninstalled the software FoxOne and all get fine again.

I went out for approx 3 weeks , for Christmas vacations , and when i returned the flicker start again, in the dvdrips and other videos the image start to stutter , or it gets a weir flicker in top left corner
in games it cause a small flicker , for instance in Crysis , the EA , NVIDIA and INTEL EXTREME intro videos , appears some horizontal bars flickering, and the game itself gets some flicker every 30 - 45 secs.

So this is what i have tried so far:
I have erase and installed the nvidia force ware 169.31, and 163.75
Formatted the pc and re installed just the needed drivers.

results : none

The only way i get no flicker in the intro videos of crysis , and random small flickers after 1/2 hour playing is with the drivers 97.95 that i downloaded from guru3d , but the movies still looking bad.

My system is:
Core 2 duo E6750
thermaltake big typhoon vx CPU cooler
MB foxconn P35A-S
PNY 880GTS 640MB
4GB DDR2 800 Patriot memoriy (2 x 2gb)
Western Digital 500GB Sata2
Ultra xconnect2 550W

All the temps are OK i have check it , the gpu reaches the 75ºC at full load.

I don't know what else to do , any suggestion will be greatly appreciated. Sorry for my bad English