Identity Safe Not Working

I'm running Vista Business (up to date on Windows Update) and NIS 18.6.0.29 on a laptop and for no apparent reason Identity Safe has just gone away. All settings are OK (and haven't been changed recently), I'm logged in to Identity Safe but it's not inserting userids/passwords, nor is it asking me whether I want to save same when I do??  Any clues anyone?? Only recent changes I've been aware of are the normal Live Update sessions, which are up to date....I ran a NIS  Support scan which said 'no issues'