I am unable to install Mcafee products on my PC as the RAM available is insufficient (requires at least 256 MB). I am told by Mcafee that the system has only 128 MB of RAM. I replaced one of the slots in the PC with a RAM board a few years back. The maximum capacity for RAM in the PC is 512 MB. Do I replace the RAM in each slot (have 2 slots) with a 256 MB RAM board?