Thanks to all for your help. I ran System Restore back to Thursday, then tried to run Poser -- nothing. I reinstalled Poser and the service releases on top of it. It runs Pro Pack now, though I still cannot reinstall Pro Pack -- Also the following error appears: Cannot open script for reading: (PEPythonEngine::DoScript()) So I have version 4.2.1.179 running now. I still would like to reinstall Pro Pack so everything is a clean install. Any ideas?