Have you updated to 8.1? I haven't had any problems with it, save for one thing. When you print either "all odd pages" or "all even pages" of a pdf file that has and odd number of pages, you'll miss the last odd page, and have a double last even page. But this problem was absent in number 8.0. Never had the problem you're describing. Have you tried contacting Adobe? Are you saying that there's no such problem listed on Adobe's support site, or that they say there's no such problem (well, prior to your case.) Try uninstalling it and downloading the latest version. That sometimes works. My brother has a case where upon exit, Oblivion would freeze, and later pop up with an error. I had that with F.E.A.R. Updating to the latest version, and un/reinstalling seemed to help both cases.

btw, what other pdf readers are out there?

edit: "unkillable" you say...Have you tried Process Explorer? Windows Task Manager isn't exactly the best process monitoring tool around.