The motherboard only has the one slot so you don't have a choice as to where to put it. Did you make sure that the card was seated all the way into the slot? You made sure to connect the power cable to the card?
tried disabling the On-Board GPU, still doesn't work. since 8800gt consume big watts, tried using diff PSU still doesnt work, tried different DDR3 ram. still doesnt work.
but how come it works on an G41 mobo -______-