I'm not sure if that's posted before. But that's how I solved my "LW won't open" problem and hope that helps.

I am a vista user and just installed Limewire. After I started the application, the title screen appears and then disappears in seconds. Nothing happens then.

I tried to reinstall java, LW, antivirus software etc. But the situation never changed. I can run LW in compatibility/Win 2000 mode. But the font was blurry and aero would be disabled too.

Then I find a key symptom. I can't open my java control panel. (via the java icon in windows control panel) It said "could not found the main class".

I googled a lot and found that many java applications will not operate correctly if your clearfont is corrupted (and it seems happens a lot)

here's my solution:
1. download MS cleartype tuner powertoy
http://www.microsoft.com/typography/ClearTypePowerToy.mspx
(it works for both XP and vista regardless what they says)

2. run it once and it will reset your clearfont.

Now I can run LW perfectly without compatibility mode. I believe that my clearfont was corrupted during one of the windows updates. So I think I'm not the only one who may have this problem.