I guess you're using Vista? Do you mean that you deleted LW's preferences folder here: C:\Users\your username\AppData\Roaming\LimeWire

Did you try replacing the gnutella.net file which is found within LW's preferences folder (named LimeWire)? Have a look at the thread below...there are links to download a gnutella.net file, plus more info.
Make sure that LW's completely closed first, or it's a waste of time.
http://www.gnutellaforums.com/connec...t-connect.html

If that doesn't help, post back with your system details (check that thread for info about what details we need). Also, hover your mouse over the gnutella.net file...what size is that file?