I was using a gigbyte MB and my 1st E6600 processor. I turned it one one day.. about 3 weeks ago and nothing turned on.. the cpu fan, RAM and hard drive all were working, but no picture on the screen nor were the kb/mouse lighting up. So I unplugged the system, double checked all the connections and turned it back on and nothing. It did not come up to BIOS or anything.
So, I picked up the MSI mb and tested that without success. I then thought it was the ps and picked up another one of those and tested and same thing. I then picked up a E6600(for $50) and tested last night and nada.
I then took out the video card and tried to use vga graphics and test and nothing. I then took out 1 stick of RAM and tested without success. I then took out the 2nd stick and nada.. I then unplugged the hd and nothing. The CPU fan would still run.
I tested the monitor with teh PS3 and that worked fine.
I understand that for all the new part prices.. I could have been on my way for a new system but..
Welcome newcomer, i don't think it is the bios batery as it would just try to load defaults every time. however, if the bios is set incorrectly you could get the same symptom. i would reset bios to defaults and see if that clears it up. if not, I would have to suggest mainboard issue at this point.. you have ruled everything else out.