first try reinstalling limewire, make shure you have the password and e-mail you used to get the password if you can't remember go to http://www.limewire.com/english/cont...pro_lookup.jsp
you were using when you download pro to uninstall you go to add/remove programs and uninstall there, than you delete the files, in the limewire folder, which is usually under program files. and the .limewire folder inside of documents and settings even though you say you monitor your computer some things can start to decay.
or try checking with your isp if they have something to do with it