If RealPlayer doesn't appear in Settings/Control Panel, this means it didn't install properly. To be able to uninstall it, you'll need to overinstall it first, i.e. you'll need to download a new copy of the software over the one that you have on your computer. To download RealPlayer, visit: http://www.real.com/
Once you've overinstalled the program, if you still want to uninstall it, you should now be able to find it in Settings.