Uninstall LW (start > all progs > LW & use the uninstall option there). Reboot & then use the computer's search to look for all files & folders with limewire in the name, delete whatever you find.

Now reinstall LW & make sure to use the offline installer (when you click to download & the dialog box pops up, cancel that & use the option to download the offline installer).

Do you have an old LW installer somewhere, to check whether an older version works properly?