computer turns on but no picture

this is my first custom build pc and im very frustrated about this problem im having. i have already replace both my cpu and motherboard. my computer turns on and all my fans seem to work as well as the harddrive spinning but the picture doesnt show up. 8600gt graphics card nforce6m-a motherboard amd 4800 dual core cpu 500 watt power supply help would be greatly apreciated

**DUPLICATE POST** You asked the same question in Hardware. It is generally considered poor forum etiquette to "shotgun post" the same question in multiple forums as it "appears" to be an attempt to get help before others. I responded in your other thread, so lets use that one. Thanks for your cooporation. Mods - please close.