SODIMM ERROR ! ! -please help

I have my MPC for 6 months and have added RAM and a HD (hitachi), and just this evening while I was playing it it kept freezing. I turned it off and started it back up loading everything, and it froze two more times. Now when I turn it on, on the "128 mb memory loaded" screen, it says SODIMM ERROR. I had had no problems with my MPC what so ever prior this recent problem. Please help me if you can

Try removing the little cover on the underside of the 2500 where you install the ram. Remove the ram and then replace it. Sounds like it may have come loose or something.

worked like a charm