Got an Orange MSoft warning screen on Waterfox - Yahoo tab!

I was one of there 'previews' to an article off HUFFPOST - but just scanning yahoo's short clip This Yellow screen came up with a call 855 - number for assistance ( toll free...whatever) ,and it locked up all tabs. I could exit waterfox, and it gave me the - do you want to leave this page? Shutdown allowed. Uninstalled and reinstalled waterfox, got same screen when loading the Yahoo home page. So, no more YAHOO, and so far, no "potential ransom" screen.
I had made a backup copy of the waterfox profile, but I didn't delete the 'original.' Perhaps I should try that, and see if waterfox can reinstall , build a new profile, and cure this. Not sure if this would be a user profile type of 'hit'.
Anybody else running into this? Yipee Yahoo!
I suppose I could risk it and try again, and get a screen print if anybody's that interested..