Ok there's a few things to try...If your Dads computer connects without any problems so should yours...
Let's start with your Java version...
Try uninstalling all versions of Java from the add/remove programs and then re-install the JRE 5.11 offline version....
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11
If that does not help with your problem try deleting your preference folder/s...
Fixes for Limewire when LW isn't operating as it should
If you still cannot connect tell me the make and model number for your router...
Also your symantic antivirus, what version is it...
Try this as well...
Uninstall your symantic antivirus, Uninstall your Limewire....Then re-install limewire and then re-install your symantic antivirus...