Before I went on vacation, I shutoff my computer hard by holding in the power button. I came home and can't power it back on. My girlfriend said the caps lock and scroll lock lights were on all week. When I switch off my power supply, the keyboard lights turn off. When I switch the PSU back on, they come back on, and I still can't power on my system, even hitting the switch on the mobo. The power supply is not dead, and there are no beeps. NO POWER ON!  
 
I've tried:  
-disconnecting the power cord overnight  
-resetting the CMOS  
-disconnecting the keyboard and turning on  
-verifying the power button is connected to the mobo header  
 
I am hoping I will not have to pull out the battery, because that will require a ton of work. Posting here is first before I call Tyan tech support.  
 
DOES ANYONE HAVE A CLUE????? We are talking no power on whatsoever here. This system was working without a hitch before I left, and it is plugged in to a Monster Cable surge protector. It seems to be stuck in some kind of sleep state?

your bios battery may have gone  

there is almost no possibility that I have seen or heard of that would cause a dead CMOS battery to cause a mobo not to power on (unless the battery shorted internally...possibly).
 
I suggest eliminating as much as possible from what you need to diagnose, disconnect everything from the power supply but the vid card, mobo and fans.  Disconnect all external connections except video, KBD and mouse, then power on.  If all you get is KBD lights and no power on/boot to bios then you may have a problem with the mobo or keyboard or PSU.

Tyan tech support said the same thing, rip it apart barebones style. They said maybe a faulty CPU, a burn out on the mobo, or a short on the mobo (even though I used teflon tape on the gold posts). I'll keep posting as I dive deeper into this mess.