Another possibility: do you have multiple installations of SO ? Contrary to what TC said, you can only have 1 *fully* working installation of SO, since the folder where where you install SO is set in the registry at install time, so the right DLLs can be loaded. The only way of having more than one installation working (witch is probably TC's case if all 3 installs are working) is to have the same version of the game binaries on all the installs, so that SO installed in the Z folder will work loading it's DLLs and stuff from the X folder, etc. This means, for example, that the same version of the Hi-Res patch would have to be applied to the 3 installations for all 3 to work *right*.