I read your manual and it doesnt say anything about having to open or close a jumper. Make sure your installing the ram in one of the two slots on the left (the two closest to the cpu).
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To clear your CMOS there are two solder points (#17 in diagram) that need to be connected for a short time. Unplug the computer from the wall socket, unfold a paper clip, and touch the two solder points together for a few seconds.