Please excuse the erroneous subject line. I am curious to know whether anyone has worked with MOPAC 5.0 on an IBM PC. If so what compiler did you use to get it running, were you able to find a way around the 640-kb memory barrier, and of course was it in fact worth the attempt given the limitations of the machine. Jim Schmidt University of Rochester jims(-(at)-)duce.medicine.rochester.edu ---