CX-Server is used by many Omron software products, and several can be installed on the same computer. If you uninstall CX-One from a PC, it doesn't automatically remove CX-Server. This is also the case if CX-Server has been installed from the CX-One CD. This is by design, so that other Omron software may continue using it. If you wish to remove it you need to go to the Control Panel->Add/Remove Programs to manually remove CX-Server components.