Well, with my really old machine (120Mhz, 96Megs RAM) sometimes poser4 locks while it don't find a needed file for a PZ3, but never the machine. I would suggest, install WinNT4.0 for Workgroups and you have the absolutely control over the machine. I work since two ears with two systems which have NT, at this time only 1 system-lock. SHARKEY