I think the only way to convert the file system is to reformat the hard disk which is a little drastic. You can change in and out of compatibility mode. Windows XP has a task manager that allows you to track system performance while Poser is running. You can track physical and virtual memory usage, cpu usage, After you have Poser open with the task manager in the foreground, you can load Vickie and see what that does to memory usage. With 512 megabytes, your system should be able to handle Vickie easily. You load Poser and then press Control, alternate and delete once. There are different panels including one for performance. With Poser loaded, check the memory usage against the limits; then do the same after you load Victoria. You can also check CPU usage, If the memory and cpu usage are not close to the limit, you can rule out a lack of system resources.