You don't need to pull out the battery .You can use the CMOS configuration jumper.
But disconnect the computer’s power cord from the AC power source !!
It is highly recommanded to read the manual before you open the case
If the 1st led to the left of the mobo power button is on ,it means that you have the +5V standby voltage from the power suply. You have to check your power suply if the PC doesn't start (No spinning fan, green lights, etc) without any extension cards added (Video, Soundcard ,etc ).
If the PC start without any card inserted ,it means that you have trouble with one of the extension cards.