I am starting to put all the pieces together on my new computer.  I have ASUS P5K-E LGA 775 and Antec Nine Hundred case.  I believe I have all the connectors in place.  When I press power button is starts for the second then shuts off (no beep at all).  I disconnected HD, CD/DVD, firewire, USB connectors.  Get same outcome.  I removed a stick of the memory "cm2x2048 - 6400C5".  Also swap it for other memory stick, to see if that was issue.  I removed EVGA 8800 GT card still get same.  Again same outcome.  If I install the video card and don't connect the secondary power cable I get a short beeping sound.  I didn't make any changes to the jumpers on the motherboard but I didn't think I had to.  There were three connectors for power, HD, reset, they are all connected.  What could be wrong or what am I doing wrong?
 
-Chris

lol.. figured out.. I didn't connected the second power connector to the board.  I haven't dealt with board that needed two different sets of power..  on to the next pitfall..

you know... I was almost going to mention the power to the mobo, but I figured you knew bout that... next time I'll just say it!  Anywaysss.. glad you got it working!

 
This is very common today. A lot of people make that same mistake.
Congratulations on getting it right that quick.