What about the other new stick of RAM? Boot or no boot?
Assuming that you've got the module in the proper slot, sounds like: a) wrong type or b) bad RAM.
Check your motherboard manual to see what slot one module goes into - not unusual for it to be the slot closest to the CPU. Verify the type of RAM including buffered/nonbuffered, voltage, ECC/non-ECC. If everything is correct for your motherboard, RMA the RAM.