Outdated Norton Toolbar is not detected by Norton Update Center

I have 2 computers running Win XP and Firefox 18.0 and NIS 20.2.0.19, but the computers have different versions of the Norton Toolbar as an add-on to Firefox.  The happy computer has toolbar version 2013.2.3.1, which is compatible with Firefox 18.0.  The sad computer has an outdated toolbar version 2013.2.2.3 that is incompatible.

 

Norton Update Center says I have the latest NIS version on the sad computer.  It does not detect the outdated toolbar!

 

2 questions:

 

Short of entirely removing and reinstalling NIS on the sad computer, is there a way to update the toolbar?

 

How can the "same" version 20.2.0.19 of NIS have different versions of the Norton Toolbar?