If you're running (or trying to run) MeasMax ver 6, I believe Ver 19 or above is req'd for the MP firmware if its a SMP-300 (or even a MP-30/35/30-II). I believe "old" firmware (Ver 18 or less) creates lots of problems. Ditto on the other responses re: Win98 (some inherent problems), 16Mb RAM (forget it), 32 Mb RAM (marginal but will run MeasMax).