Sorry not enough room above. I'm actually running Windows XP Service Pack 3 with Firefox 43.04. I've enabled PC matic 1.01 and it seemed to take and is remaining enabled. Do I need to go back to an earlier version of Firfox? There is currently a small icon of PC Matic's Green Super Shield appearing in Firefox's top "tool bar" next to last icon on the right. It has a number appearing in a black box just above and to the right. Number seems to change starting at 1 and is currently up to 5. Occasionally the "Green Super Shield Icon" is turning red. Anywhere else but here I would say it is indicating it is updating - but I'm not sure now. Not sure how much longer I'll attempt to stay with XP, but regardless I do not want to jeaporadize my use of Firfox and XP SP3 together. In an attempt to keep from creating a problem on my on, I have activated Firefox to let me know when there is another version ready so I can avert aproblem with other Firefox changes that might make my problem worse, if that's possible!