If you have a look underneath the modem, it will tell you the make and model number, could you tell me what that is...if these tips don't work...
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