I am not positive that this is the best place to answer this question, but I'll give it a shot.
For years, I have been opening up PDFs through Internet Explorer without havng to need to open up Adobe Reader. This has saved me a good deal of work (and memory space) by not having to have yet another program open.
Recently, however, I have installed Adobe Acrobat Professional, and now, every time I try to open a PDF in Internet Explorer, Adobe Acrobat automatically starts up. Does anyone know how to stop it from doing this and how to default back to the original settings?