1st, hold down Control-Alt-Delete keys & open Task Manager. Make sure Limewire is not listed, if it is then stop it. Then go to Start menu>Programs>LW>Uninstall LW. Then uninstall. If you had previously had an earlier version of LW on your computer (LW 4.2 or earlier) then use your Add/Remove Programs control panel to remove the older version of LW. Then try installing again. If still problems then I'd suggest you clean up your registry; if you don't have a registry cleaner then see:
HERE (click on link)