Try opening your task manager(Ctrl+Alt+Delete), and see if it's listed under Processes. If it is, right click on it and end the process. Then try reinstalling. The proper way to uninstall LW is by going to C:\Program Files\LimeWire\Uninstall.exe. Double click Uninstall.exe. Don't go through the Add or Remove Programs Control Panel.
Where you having any problems with it that made you want to uninstall it, like it opening up on it's own? If so, that's caused by a virus.
See:
http://www.gnutellaforums.com/genera...tml#post288817