If you are a Firefox user, you must experienced all firefox windows froze while opening the pdf file. While the pdf file is loading, all of your browser windows are frozen and you can’t do anything else. It is because firefox is loading using pdf plug-in for firefox. Even crashes your entire browser sometime. So while bother using plug-in, if you can open all pdf file using acrobat reader itself. You can browse something else with your firefox while it is loading. Here is the trick:
1. Go to the “Tools -> Options” menu
2. Select the “Downloads” tab
3. Open “View and Edit Actions…”
4. Enter “pdf” in the “Search” box
5. Select “Change Action…”
6. Change the selection from “Use this Plugin” to “Open them with the default application”, which should point to Adobe Acrobat Reader, or your favorite PDF viewer.
7. Click "OK", "Close", and "OK".
Now when you open any pdf file from Firefox. It won't freeze your firefox and load the pdf file with Adobe Acrobat Reader, or your favorite PDF viewer instead.
All credit goes to XForms Everywhere
Update: I don't see that problem in Adobe Reader 7.0 and later versions anymore!