The only way for you to delete your shared files by reinstalling LW would be if you stored your shared files inside the LW program folder. Never a good idea. The default location for downlds is: C:\Documents and Settings\"your account name"\Shared

Yes try re-installing LW using the "Offline" version. Also do points #1 & 2 only here: Fixes for Limewire

BTW if your present version of LW is older than 4.4 then you'll need to uninstall it 1st using the Add/Remove control panel. If it's a later version then LW will uninstall it during the installation process. The reason for this is a different type of installer LW uses now. The other type of installer LW also previously used was the so-called international version which should be uninstalled via the Start menu>Programs>LW>Uninstall (or find the uninstaller within the program folder.)

Get LW here: http://www.limewire.com/english/content/download.shtml

Did you configure your firewall so it allows LW full access (advisable not to have 2 active firewalls b/c they can interfere with each other); Firewall configuration instructions (click on link)