Cannot open .pdfs in Firefox

Question

My wife's machine is running Windows 8.1, Firefox 34.0.5 and Adobe Acrobat X Standard. Cannot open .pdfs in the browser. Clicking a link to a .pdf will open a new tab that immediately closes, leaving me right back where I was, as if I had never clicked the link. I can right click, then Save As, download the file and open in Adobe Acrobat X. But that's not what I want, and not how it was designed.
Internet Explorer 11 opens .pdfs in the environment described above, in-browser, with no problems.
I've followed all the instructions at https://support.mozilla.org/en-US/questions/972278 and http://helpx.adobe.com/acrobat/kb/cant-view-pdf-web.html. Neither Mozilla's nor Adobe's instructions can get me up and running.
As a nuclear option, I uninstalled Adobe Acrobat, restarted the machine, uninstalled Firefox, restarted the machine, re-installed Adobe Acrobat, restarted the machine, and re-installed Firefox, and restarted the machine. Attempting to open any .pdf yields the same result, even after uninstalling and re-installing everything. What's going on here? Why does Firefox open a blank tab, and then close it right away? Block pop-ups is set to off, and antivirus pop-up blocking is disabled.
My own machine running Windows 7, Firefox 34.0.5, and Adobe Acrobat X Standard opens .pdfs in-browser just fine, with no problems.
Any advice? I'm pulling my hair out!! Thanks for your time.
kjbgu04

Answer 1

Hey,
Try the following:
* Go to setting (3 bars) > options > applications.
* Under applications panel.
* Find Portable Document Format (PDF) in the list and click on it to select it.
* Click on the drop-down arrow in the Action column for the above entry and select Use PDF reader name (in Firefox) or preview in firefox.
If PDF files are still downloaded instead of displayed, try these solutions
Reset download actions
* Open your profile folder:
Click the menu button[[Image:New Fx Menu]], click help[[Image:Help-29]]and select Troubleshooting Information. The Troubleshooting Information tab will open.
Under the Application Basics section, click on Show Folder. A window with your profile files will open.
Click the menu button[[Image:New Fx Menu]]and then click Exit [[Image:Close 29]]
Delete the mimetypes.rdf file.
Then open firefox again and see.
I hope it helps.