Update your Firefox.

Update Adobe Reader

You can download it from http://www.adobe.com/products/acrobat/readstep2.html
After installing the latest Adobe Reader, uninstall all previous versions.
Note. If you already have Adobe Photoshop® Album Starter Edition installed or do not wish to have it installed UNcheck the box which says Also Download Adobe Photoshop® Album Starter Edition.

Alternatively, you can uninstall Adobe Reader (33.5 MB), download and install Foxit PDF Reader(3.5MB) from HERE.
It's a much smaller file to download and uses a lot less resources than Adobe Reader.
Note: When installing FoxitReader, make sure to UN-check any pre-checked toolbar, or other garbage.
On this page:



make sure, you have both boxes UN-checked AND (important!) click on Decline button