If you use Windows XP or below, navigate to Start > Control Panel > Add or Remove Programs. In the "Currently installed programs" box, click on the RealPlayer program and then click Remove.
If you have Windows Vista or above, you need to go to Start > Control Panel > Programs > Programs and Features. Select the RealPlayer application and click on Uninstall.
After that, download and install the latest version of RealPlayer. Also, you can install RealPlayer Cloud which superseded the application.