Adobe Reader

I can't read PDF. I get message:"Cannot use Adobe Reader to view PDF in your web browser. Reader wil now exit. Please exit your browser and try again". I have Adobe Reader 8.1 installed. I've tried repairing the installation but didn't help. What do do? Thanks

As Adobe Reader is FREE, why not simply go and get the latest one that's available here: Adobe - Adobe Reader download - All versions (http://get.adobe.com/reader/)