New build, no start

New build consists of
Mobo-Biostar P4M800-M7A socket 775 Micro ATX
Ram-2 Ultra 513 DDR PC3200 dual channel
CPU-Celeron D 3.2 socket 775
PSU-Ultra 500W ATX
HD-Seagate serialATA 160G
After assembly, computer would not start, not even a post beep.
CPU fan is running, fan and hearsink are new. Disconected floppy drive and optical drive, still no start.
Replaced mobo wih another (new, same model). No change. Swapped PSU. with a spare unit, still no start.
Switched ram module slots, NG. Removed ram mod. one at a time, no change. After all this, still the only thing that starts are the cooling fans, and still not even a post beep.
Never had this kind of problem before. I would appreciate any help.
Thanks, yokems

 

Did you place the motherboard standoffs in the correct location? Have you tried to lay the motherboard on a non-static bag outside of the case with everything hooked up then tried it? It is possible the motherboard is shorting out in the case.

 

The standoffs are correct, I even tried a different case. My next step will be your suggestion to remove mobo and try out of case.
Thank you for your help.

 

Some possible areas:
Biostar CPU support:
http://www.biostar.com.tw/support/cpu/socket_775.php3
The motherboard supports Celeron D 351 3.2Ghz (cache 256K). It does not support Celeron D 352 3.2Ghz (cache 512K), if you happen to have that model.

There is a thermal pad or you have used thermal compound to install the heatsink?

You can remove the RAM completely, it should give "no RAM" error beeps (check the system speaker is connected correctly).

Do any LEDs flash on the drives or keyboard? If not, I might suspect a problem with CPU or RAM. If yes, I might suspect a problem with the graphics. The motherboard has onboard graphics, so it may need to have the CMOS "cleared" to set it to onboard graphics (read in the motherboard manual how to clear the CMOS).

Matt