7800gs+ problems agp

Hi all
I m a newbie here

my recently acquired 7800GS+ 512mb is not running correctly;
my screen turns black after installing the drivers and at windows start
it gives vert and hor stripes of colors
anyone has a clue
thanks
my specs are
board p4p800
p4 3GHZ
2gb ram
450W trust psu
1 HD
1 DVD
1 CD
thanks a lot

 

here is hoz the screen look like

 

Hi again folks
now i m desesparate
I installed every possible drives even nog modified version; all that happens is that once windows is loaded (after the logo) the screen goes black as if no signal comes out the card altouth it s still running.
I ll write to Gainward cuz the card is giving me problems at the very begining when the cpu boot so i guess it has nothing to do with drivers since nothing is loaded yet...

 

reqsolved

HI I just called Gainward
Apparently I overclocked too high even for a short period of time (i did it for a few minutres) and it was enough to kill the memory.
About 70 of these cards were sent to repair and loose their warranty.