New System First Boot Problem

[Phyrestar]

Well I just put together my first computer and lets just say that it hasnt been worth the hassle yet. When I first tried to boot the computer everything powered on but there was no signal to the monitor. I called the Asus Tech Line and they explained to me that I either have a bad CPU, Motherboard, or RAM. Then they proceeded to tell me to figure out which one was the culprit by testing all of them out. Well how am I supposed to test everything out? The only thing I could test was swap a different Graphics Card in from my Bros Computer. How will I test everything else? The Tech also explained to me that it has to be one of these things because the POST is not coming up and it cant be the PSU as the LED power light on the mobo is green and on. The new system i have is running on an Asus A7N8X Deluxe Mobo, AMD XP 2600 w/333 FSB, 1 gig of OCZ PC-3500 EL RAM. I have a 480W Antec True Blue PSU. I need some quick feedback because I have a deadline to return these pieces by the end of the week. All help is appreciated thank you.

[Mr. C]

Check your motherboard mounting screw and all around the board in general to ensure you're board is not shorting out against the case -- check that any cards or slot covers are not shorting the board as well.
Check each cable and connection to make sure it is as it should be.
If you have more than 1 stick of RAM try them 1 at a time instead of all at once - repeat for all sticks.

Is your heatsink fastened properly to your CPU?
Is the thermal paste applied properly?

remove all the PCI cards if any are in place -- 1 step at a time is best.

Have you got access to another PSU to try in that system?

well, I covered most of the basics I believe -- Good Luck!