As already suggested, get in touch with McAfee and potentially install it again from a fresh download. This certainly smells like something took over your computer. Clean your computer from all viruses and other nasty ware and then download a fresh install of Reader from Adobe's server. This way, you get the latest and more importantly clean update.
Karl Heinz Kremer
PDF Acrobatics Without a Net
PDF Software Development, Training and More...
http://www.khkonsulting.com