Avg pc tune up .....pdf files issue

Bob, Have a look @ this article (http://avgclick.me/restorechangesbyAVGPCTuneup).
AVG Guru

Hi there, i have a paid for subscription for 2 years with AVG. Yesterday i did some AVG PC Tune Up on my computer, and now i am unable to open up PDF attachments.  When clicking to open the PDF file it automatically goes into the Internet into blank. Can someone please assist in reversing this, as i may have inadvertantly clicked on an icon to this setting whilst cleaning up my computer. Thank you.

Bob, Have a look @ this article (http://avgclick.me/restorechangesbyAVGPCTuneup).
AVG Guru