It sounds like you updated to XP SP2 right? This has caused so many people problems. Some have even uninstalled it.
Configure your firewalls to give LW full access:
http://www.limewire.com/english/content/firewalls.shtml (ie: XP firewall & any other you have.)
Try to force ip:
Force IP instructions & sample image
Go here:
http://www3.limewire.com:6346/ & it should say Test Page was a success. What happened for you?
Update your Java:
Java 1.5 (take the JRE) (LW needs the latest.)
So you're trying to connect at uni. Are you also trying to connect at home without success?