Double check that ZA's allowing LW & that the XP firewall is off.

Delete LW's preferences folder when LW's properly closed. See point 3 here & also point 2 if you've used older versions of LW in the past (there could be a folder in either location).
Fixes for LimeWire
This will kill all of your settings within options, you'll have to go back through afterwards & reset things. If you're not sure of your settings, go through LW's tools > options & write them all down, so that you can reset things later.

Try port forwarding for your router, the instructions are here.
Port Forwarding for the Linksys WRT54GS
Don't forget the step of setting up a static IP address first. LW's listening port, port in the 'manual port forward' box & port forwarded within the router all have to be the same number

Were you using Java 1.6.0_01 on the other account, when LW was working? If you weren't, try this version of Java. Use the offline installer & remove your current Java version before you install this one.
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11
Some people have had problems with that latest Java update, others can use it just fine.