Make sure the battery is good and you can use a volt meter to see if the pins off the batter holder are making good contact (ie have power from battery...do this no plugged in...i think its 3.3V but whatever V the battery should be).

Looking at the manual.

Check the RTC clear jumper.  Make sure there is no jumper on the two pins.  Its on page 1-11 of the manual.  This is used to clear and reset the bios.  The normal procedure is to remove all power and short the pins for a few seconds. to blank the bios settings.  Then remove the short and repower the system.  Check if this is jumpered if it is remove it and it may take a bit but the bios should allow you to program it and save it with a good battery.

Thats the easy stuff.