Did you go through the "Connection problems? Check here first" sticky? If not, please do...there's a link somewhere at the start of this thread. It's better to have your firewall configured rather than turned off.
How do you have your router set up (UPnP enabled, port forwarded or nothing)?
Have you tried enabling UPnP or port forwarding?
Where are you connecting from (home, work, school, student accommodation etc)?
Are you sharing a connection with other computers?
If you're using SP2, have you tried any connections patches (like I mentioned in my last post)?
Who is your ISP?
What version of LW & Java are you using?

I have checked the sticky, I did so before I posted. I don't know enough about my router to mess with it right now, though. I am running SP2 and have not yet tried the patches, but my ISP is some generic system set up by my dorm. I don't think Limewire is blocked, as it worked earlier.

You might want to check with the school's internet admin to find out if they've changed anything since LW used to work for you. Ask if their policy re p2p has changed. If other people are using LW successfully, find out what steps they took.
A lot of, if not most, schools block p2p.

Ipod or Itunes question. Can I move songs to my ipod or itunes from limewire?