Try installing Adobe Acrobat Reader DC. It has worked for me (opening PDFs within the Opera browser)on Win 7 Pro and Win 10 home and Pro. Opera seems to have the underpinnings of Chrome so when in doubt, think like a Chrome user...!
Do more on the web, with a fast and secure browser!
Download Opera browser with:
- built-in ad blocker
- battery saver
- free VPN