NIS Win 8.1 occasionally Quick Scan, Full Scan etc won't work

Hi,

(Tried posting this earlier but don't see it so trying again)

We're finding (on two Win 8.1 laptops) occasionally NIS gets into a state where Quick Scan, Full Scan etc won't click and run and no amount of live updating, shutdown/restarts etc help.

Is there a solution to this because when it happens the only thing I can find that works is uninstalling and reinstalling NIS and that's now getting tedious.

Many thanks,

Rowantree