I would check to make sure everything in the machine is compatible with each other. detailed specs would be nice.
Also check the settings in the CMOS, I had the problem with an ASUS MB that the video card was fighting the onboard, even though it was disabled, it took a while but I got it working.
Also check jumper settings for your MB. Look at the manufacturers wevsite
AMD Duron 1.5
10/100/1000 Mps LAN
Windows 2000 Server
Windows XP Corp. Pro.
nVIDIA Geforce 6200a 512MB