New here hope you can help.

Hi guys, i've just built my second pc ever and have encountered a problem i hope you can help with. I assembled the system in much the same way as i did my first system with very similar specs, however when i turned the pc on for the first time the fans start up and i can open the cd trays etc, but there is nothing on the screen. I had a similar problem with the first system i built and solved it by removing the ATI graphics card and replacing it with an older nvidia card until i could install an os and subsequently the drivers for the newer card. I thought the problem would be solved again in much the same way, but when i attempt to do so, i still have nothing on the monitor. I have tried 3 different monitors to see if the problem could lie there, but nothing. I also attempted to use the s-video out to a television but i just get a blank white screen with the older card and nothing with the newer ATI card. When the power is turned on i get a single beep, which when i checked out i find to mean that everything is ok. I'm pretty sure this must be a graphics card problem, but have used all 3 of my available ones and still no luck. I have tried to reseat the card numerous times and have also reseated the ram. I have disconnected everything except the graphics cards and the ram and the cpu and fan etc, but still no luck. Could really do with some help.

Specs:
Abit KV7 motherboard
AMD XP 2600 Barton Core
512 Mb DDR400 SDRam
160 Gb hard disk
ATI Radeon 9600 pro 256Mb
350W Psu (came with the case)

 

The AGP slot on the Kv7 is really tight with the latch against capacitors, really make sure you seat the card in fully.

 

Also are you getting any beeps when trying to boot up?