I'm helping my brother build his rig.
He has an ASRock 775 XFire-VSTA
Pentium 4 2.8 Ghz
1GB DDR 2 533 Mhz
400W PSU
Geforce 8400 512 mb GPU

When I power it on, the led on the monitor stays amber,
and I get no display on the screen. Any help, please?