I have this bizarre bug with my Asus P5QL-PRO motherboard: each time I go to sleep in OS, and the sleep is interrupted by power off event, on the next start the motherboard does the following:
1. Screen is off
2. No post signal
3. Fans continue to spin
4. Machine starts, then stops, then again starts
When I hit this problem for this first time I though my mobo is dead. After some googling it revealed that a CMOS re-set should help. So, remove CMOS battery, change jumper from 1-2 to 2-3 position, wait for 10 seconds and put everything back in reverse order.
Yesterday I got the same behavior after attaching some devices to mobo (I was rerouting USB devices from case), but CMOS reset did not help. I left machine with reset jumper in 2-3 position for two hours and still no results. So I started to unplug devices one by one trying to determine the cause. Once I removed memory – it all started to work perfectly :). I guess I might have touched the memory and it slightly got out or I have a new glitch with memory 🙂
Anyway, I put everything back again and now it works.