Daniel,
1. Open Adobe Reader>Preferences...>Categories>Internet>Web Browser Options> [ ] Uncheck "Display PDF browser using:"
2. Quit Safari or any other browsers.
3. Then, in Finder navigate to:
Macintosh HD/Users/yourusername/Library/Internet Plug-ins
(or) Macintosh HD/Library/Internet Plug-ins
(and) move the Adobe PDF Viewer plugin (I no longer have it installed to give you the precise name) to the Desktop.
4. Restart Safari or your desired browser.
If you have different PDF Viewer/Browser plug-in other than Adobe, just use the same procedure.
You can reserve the PDF viewer or trash it at your discretion.
;~)