-> click Firefox button and click Exit

-> Start Firefox in Safe Mode (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

https://support.mozilla.com/kb/Safe+Mode

Firefox Safe Mode window will open. DON'T SELECT ANY OPTIONS, just click Continue in Safe Mode

Check and tell if its working while you are Browsing and Downloading files in Safe Mode.

Followed your instructions and unfortunately it is still not working properly.

were you able to download any file while you were in Firefox Safe mode ??

No the same thing happened, the download dialog box opens, when I right click to open the containing folder the option is greyed out. I tried downloading a .exe file as well, and once again no luck.

See these:

• Basic Troubleshooting https://support.mozilla.com/en-US/kb/Basic%20Troubleshooting

• Troubleshooting Plugins https://support.mozilla.com/en-US/kb/Troubleshooting%20plugins

• Resetting Preferences https://support.mozilla.com/en-US/kb/Resetting%20preferences

Check and tell if its working.

It is possible that your anti-virus software is corrupting the downloaded files or otherwise interfering with downloading files by Firefox.

Try to disable the real-time (live) scanning of files in your anti-virus software temporarily to see if that makes downloading work.

See:

• http://kb.mozillazine.org/Unable_to_save_or_download_files