If you're using McAfee's firewall, make sure that the Windows firewall is off.

Have you tried all of the fixes here?: If LW Will Not Connect

You might want to check that your school hasn't started preventing people from using p2p on the school network...can other people use p2p apps at school?

Have you always seen the firewall icon (brick wall), even when LW was working?

I tried it with McAfee off and Windows on, and vice versa.

Tried every fix on there. (some twice)

A girl in my hall used Limewire yesterday just fine

And I'm not 100% about the brick wall, i never really paid attention to it. But if my memory serves me correctly, I'm pretty sure there was no brick wall. Granted, this started happening about 2 weeks ago and absolutely NOTHING changed related to LimeWire (other than the latest update) and my firewalls (other than the daily McAfee virus definition updates)

Which version did you have when LW worked? 4.16.7 hasn't been out for 2 weeks...did you also have probs with the previous version?

After you deleted the prefs folder...did you have to go through LW's setup wizard again?

Go & find your gnutella.net file...what's the size of that file?