Hi this is my first thread, and i hope i can explain myself so that thos'e with greater knowlage can understand my frustrating problem, and give me the help that i so desperatly need.
this is the rig i built 3 months ago

MB Asus Striker Extream
Intel core2 Quad Q6600 2.40 ghz
Thermaltate Shark Case
Thermaltake 700w PSU
BFG nvidia geforce 8800 GTS OC 640 MB
XSPC X20 Mini Delta water cooling kit
Seagate 500GB sata11 16mb cache 7200 RPM OEM
Corsair Dominator PC8500 4GB XMS2
OS Vista Ultimate 32 bit OEM Build 2-23-07

During normal use i dont seem to have any trouble, every thing is working as it should, the problem i am getting is when i try to play games! any games, the only way i can explain what happens is by saying "BSOD" as im sure you ar all aware of this meaning, but this is not what i get, but very close to it. When i actually play a game it runs for a short time then all i get is a blank screen, it can be any color of the rainbow, no warnings like the BSOD just plain colour, and the sound of the game continues as a reverb note, i cant restart using ctrl-alt-delete i have to reboot each time, sound card is a BFG replacement as my first card would not boot to post.
Many thanks to all that can help shed some light on this subject

this sounds pretty much like some hardware error with the graphics cards
the first thing I would try is to deinstall the nvidia GPU drivers;
restart;
run http://phyxion.net driver sweeper for nvidia graphics drivers;
an reinstall the nvidia driver http://www.nvidia.com/object/winvista_x8..._whql.html

if this does not help (and I doubt it)
I would try you card in another PC and/or any other graphics card in your pc

again this sounds like something very serious with the GPU

oh and a 3rd thing you can try is to manually downclock the GPU to the 8800GTS defaults with http://www.guru3d.com/rivatuner for example

Hi Mertsch
Thanks you for this info, i did try uninstalling and reinstalling driver as you said but still the same problem, placed card into different mobo same problem, so it might be a second duff card,

i did try to downclock but problem seems to persist. and after reading your response i have contacted BFG and explained to them what is happening, waiting for their response and hope they are willing to help.

Thank you for your valued help and if BFG sort my problem and give me an explanation i will post reply for your interest