Terry -- here's something to try, can you find any PDFs in your File Explorer, maybe in your download files?? You can do a search with *.PDF in your Search box (if you use Windows), look for something on your computer and not on the internet.
Try opening one of them without the internet open -- some malware and such can be pretty invasive and could be set to just the action, in which case I'd do some basic virus scans and such.
Adobe now makes you pay for a number of features that used to be free, but I would trust this link for a fresh install --
https://get.adobe.com/reader/