Brand new system problems, help

[MasterMike]

Got my new system delivered today, here are the specs:

Intel Pentium 4 805 Dual Core "LGA775 Smithfield" 2.66GHz (533FSB)
Enermax Liberty 400W ELT400AWT ATX2.2 PSU
Corsair 2GB DDR2 Value Select PC5300 Dual Channel Kit
Gigabyte 8N-SLi Pro nForce4 SLi (Socket LGA775) PCI-Express Motherboard
Seagate Barracuda 7200.10 320GB x2
BFG 3DFuzion GeForce 7600 GS 256MB DDR2
Zalman LGA775 cooler
Antec Super LANBoy case



I've assembled it all, and it took a fair few punches of the power button to get it to do anything to begin with. Now, all fans power up, the keyboard has power to it, but it occasionally reboots immediately after booting, and there's no picture. I've tried moving the GeForce to the second PCI-e port, but to no avail.

Now it's been a while since I've built a system. Is there something specific I need to do for PCI-e? Any idea what I should do next?

EDIT: It also sporadically turns on without me pushing the power button...

 

[Gandalf501]

Faulty power button on your case? Have you tried it without connecting the power button.

Use a screwdriver to short the power switch pins on your mobo.

Or leave it disconnected to see if it boots by itself.

 

[semi-pro waster]

Have you checked your system for any shorts? Could possibly cause the intermittent faults if it is only touching occasionally.

I don't know if the graphics card needs its own power connector but have you checked that?

 

[SiriusB]

Are all the other necessary power cables attached to the motherboard as instructed by the manual?

SiriusB