New Build Does Not Boot

[TranquilRed]

Okay so I just got done building my friend a computer. All of the cables are connected, all mobo jumpers are at the defaults. The RAM is dual channeled on channel A, DIMM's 1 and 3. After connecting the keyboard, mouse and monitor, the computer does not boot and the only response at all is from a yellowish LED, labeled LED 1, just above the PCI slot. The specs of the computer are:

DFI LAN Party Expert SLI
GeForce 7900GTX 512MB
TruePower 2.0 550W PSU.
Creative Audigy ZS Pro.
2x DVD RW drives
FX-57 w/ XP-80 Heatsink
Logitech G15 keyboard

If I left out anything that might be important, let me know.

 

[Antheus]

a bit more info prolly needed. Does it turn on? CPU fan start spinning? Try booting with the barebones to see if you can isolate the problem. Also make sure the PSU is set to the rightv voltage setting. Are there any error codes for the motherboard>

 

[TranquilRed]

After fiddling with the reset switches, the computer did boot up. All internal mobo LEDs do come on, all fans spin up, the monitor turns on but gets no signal to it. The DVD drives do not open or get power as it would seem.

 

[L1ght]

Make sure the 4 pin CPU power cable is attached. CPU seated right? Ram seated right? Got a extra PSU to try? Video power cable plugged in? Video Card seated right? Start replacing the core parts if all else fails.