It's located in the bottom-right corner and at a diagonal (JBAT1).
Unplug the PSU from the wall socket for 5 minutes, then move the CMOS Jumper for 5+ seconds (XXO) -> (OXX) -5+ sec-> (XXO), plug-in the PSU and press the Power button, boot into the BIOS and Load Optimized Settings and Save (p 3-28).