Jack Steele

I have an M91-2-T1 that is not communicating with my PC. It told me that the Operating System in the control was out of date and then I was able to upgrade the software. It put the PLC into Bootstrap mode, upgraded it and then told me that communications had been established but after that I will get the standard error message about restarting the PC, M90 Program or control. How can I link with it to upgrade the operating system but NOT be able to upload the program that is running in it so that I can modify it? It says that it is unable to open Port 1. I am running XP, do I need a driver so that I can communicate with this PLC?