A7M266 blackOUT on me. Help pls!!!!!!

[Eddy]

I juz assemble my system with :
Asus A7M266
256MB DDR ram
Asus 7700 GeForce 2 GTS 64MB
CoolerMaster Casing (ATC-201-MX with 300Watt PSU)

It's suppose to be a great mobo, but when i reboot from BIOs, it hangs. totally blank on the screen. And there's a long BEEP! Check the manual is says DIMM undetected. But i doubt so..it's a virgin RAM. Juz receive from Fedexpress today.

Wat do u guyz think could be the problem here?
Do i need to buy a new DDR Ram or PSU for testing?

 

[dolphins]

Trying doing the most logical thing before going out for ram or a psu. Power down open up your box and physically reseat everything one by one, make sure youve plugged in everything correctly. Try booting up again.

 

[Eddy]

i've tried reinserting the AGP card (Asus 7700 GTS 64MB DDR) with the rest of the PCI slot cards removed. plus all other power cable for fans, drives removed.

STILL Ain'T working..