The preferences folder was called .limewire in much older versions...you might not have a .limewire folder. The new location is C:\Documents and Settings\your username\Application Data\LimeWire.
The App Data folder's hidden by default, so you'll need to show hidden files & folders to see it (control panel > folder options > view > check the radio button to show hidden files & folders > apply > ok).
If you're using Vista, see this LimeWire Pref Folder in Vista

Make sure LW's properly shut down before you delete the prefs folder. Remember, all your LW options will revert to default so you'll have to go back through & reset everything afterwards. Providing LW opens.

Which Java version did you install??? Was it 1.5.0_11?? Did you make sure to use the offline installer & remove any other Java versions before reinstalling?
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11

When you reinstalled LW, did you use the offline installer?

Right click on the LW icon on your desktop > properties > compatibility. If you're using XP, try running in compatibility mode for Win 2000 or NT. If you're using Vista, try compatibility mode for XP.

See if these help with the blank screen.
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