If you are having trouble viewing documents online, you may need to update your Acrobat Reader. Check the version of your Reader.  Run Acrobat Reader and click Help, then click About Acrobat Reader... and see if you have version 8.0 or later. Visit this site http://www.adobe.com/products/acrobat/readstep2.html to download the latest Reader for free.

The first time you run Acrobat reader it will ask you to accept the free use guidelines. This acceptance button may hide behind your internet browser. Minimize your browser to see if Acrobat is hidden underneath the browser.

"I print a PDF from the Internet and all I get is a blank page. Why is this happening?" Because you are using the Web Browser Printing rather than the Acrobat Printing.