To access bios you need keyboard and ram installed. The cmos battery basically gives the motherboard power to hold the bios settings in memory while computer is turned off and unplugged.
I would still rebuild the machine outside of the case to diagnose. It's been 3 days since you first posted your issue and you are no further along now then you were then. It's time to start diagnosing by following members instructions.
I would still rebuild the machine outside of the case to diagnose. It's been 3 days since you first posted your issue and you are no further along now then you were then. It's time to start diagnosing by following members instructions.