How did you uninstall LW? If you uninstalled through add/remove programs, that's the wrong way & can cause problems. Open task manager & see if there's a LW process running. If there is, end the process. Use your computer's search to look for all files & folders with limewire in the name. Delete what you find. Now try reinstalling the new version & see if it works.

The correct way to uninstall is by using the uninstall option, either via start > all programs > Limewire or C:\Program Files\Limewire.
Installing a new version will also automatically remove the old version first