powercolor 3850 no display help!!

i recently purchased powercolor 3850 256 ddr3....i got asrock alivexfire esata2 mobo...750 psu...2 gig ddr2..amd 64 x2 4800++ cpu.... after installing new 3850 with 6 pin connector power supply i am struglling to get display on monitor....system seems to be booting up as i can hear the vista sturtup sound...now there is two dvi and one s-video port in my card.....one dvi is sending no signal to monitor as monitor goes in standby mode......but when i connect to second dvi port monitor stays power up but with completely black screen....not even boot screen....i have updated the bios to v2.60, which is the latest for mobo.....i've also tried resetting my bios millions of time but no display.....now the strange thing is when i put my old 8600 gt, everything seems to be working normally....please help......