Adobe download manager (I think) reported a problem and sent off a report to M Soft.
Meanwhile advice elsewhere was to remove the programs prior to a re-load which I duly did.
Now I cannot persuade Adobe Reader to load successfully. Flash player has re-installed although I was perturbed by sites offering Reader which turned out to be Flash!
Last time this happened someone recommended Malwarebytes and the free version plus clearing out the Firefox addons seemed to cure the issue. I now can't get Malwarebytes to load either!