Do you know the make and model of your motherboard?
can you post the full bios string on the first page as the computer boots. It's the same black and white page that shows the memory, hard drives etc and it is at the very bottom of the page. Use the pause button to freeze the screen.
We may be able to work out the model by that string.
Try this, Remove the power plug from Wall, remove Cmos battery, if there is a Clear CMOS jumper put it on pins 2 and 3 then put it back on the pins 1 and 2 now try restart with battery and plug in. You may have to press Del to get into Setup to modify the settings for CPU etc
This is your motherboard click here. switch off the power and move the platic jumper on jbat1 from the top 2 pins to the bottom 2 pins. ( it just has a total of 3 pins ) Leave it for 15 seconds. Then put it back onto the top 2 pins.