About a month ago I found that, when I clicked on Firefox browser, instead of the usual page with the default search engine duckduckgo coming up, a very plain page which just said "Search" appeared on screen with an address in the search bar which said something like "hp-search xxxxxxx". And when I entered the address I required it was clear that Yahoo was doing the search. I tried deleteing Mozilla from the Windows 10 control panel and then reinstalling it but each time I did this Firefox seemed to have been replaced by hp-searchxxxx and Yahoo. Eventually, after using an alternative uninstaller (Revo), I was able to remove and replace Mozilla with the genuine browser and search engine. I have a feeling it was when I added "Privacy Badger" or some other extension to Mozilla that the trouble occurred. Has anyone else had this problem and, if so, could they please tell me what I error I made?