Blank screen trouble

[LazyDragon]

Hi,
I'm building a computer for the first time, and I've run into a problem. When I try to start it up, all the fans spin, LEDs light up, but I get no signal to the monitor. I've tried the out-of-case setup, but got the same result. The specs for that setup are as follows:

Athlon 64 3500+
400W Antec PSU
Asus A8N-E Motherboard
XFX GeForce 7800GT
2x512 MB Geil DDR400

The RAM is from my previous system, so it should be fine (plus, I've tried each stick individually to be sure).
Unfortunately, I can't really test the other parts as I don't have anything suitable to replace them with.
Given this info, where do you think the problem lies?

Cheers,
Lazy Dragon

[ktkendall]

Check Processor and heat sink for proper installation and alignment, check vid card to be fully seated. Do you get any beep codes???

[Cricket]

Does that Antec power supply have a 20 pin or 24 pin motherboard power connector? You need one with 24 pins (ATX 2.0).

Did you plug in the extra 4 pin 12v power connector too?

Cricket

[Spearball]

Like i said to someone else.. make sure the ram is properly in the slots.

[Science_guy]

Do you have the 6-pin molex power connector plugged into the video card? Also, asus boards can be picky about ram. I notice that Geil is not on the qualified vendor list:

http://pt.asus.com/products/mb/qvl/a8n5x_QVL.pdf

[LazyDragon]

Originally Posted by Cricket Does that Antec power supply have a 20 pin or 24 pin motherboard power connector? You need one with 24 pins (ATX 2.0). Did you plug in the extra 4 pin 12v power connector too? Cricket

Well whaddya know... I hadn't plugged in the extra 4-pin! I don't know how I managed to miss that.

Thanks for the help, everyone!