Usually programs are installed into C:\\Program Files, and thus you\'d find Planeshift in C:\\Program Files\\PlaneShift Crystal Blue. If nothing is there, or if the PS directory doesn\'t appear at all, either you didn\'t install the client or you uninstalled it after. The pssetup.exe application should be within that PS directory. Or if you think you installed it elsewhere, use the Find option on your computer.
If nothing comes up, try installing (which may mean redownloading) the client again.