Besides an uninstall, I've used this registry cleanup tool in a manual mode (just removing Acrobat entries) to give the installer a clean start. http://www.jv16.org/
It's also noteworthy the Acrobat has failed on many office machines to operate inside a web-browser. Adobe doesn't offer any cure for that issue but just notes to uncheck the web integration box. I can't fix that and apparently neither can Adobe.
In closing, you want to be free from all parasites with a clean scan from http://reviews.cnet.com/5208-6132-0.html?forumID=32&threadID=1313&start=0
have used this program for some time. had a lot of windows open including several internet explorers including one or two open to pdf files, as well as having a main reader window open as well. had some kind of problem and had to close windows. now can't load reader. reinstalled twice including full download from adobe, without success. at one point while trying to close things in task manager i received a message about "font changer" (or something like that) being unable to close properly. when i try to load reader i get the first screen with all the patent numbers, etc, but that's it. in task manager it shows that acroreader is using about 90% of my cpu, but nothing happens. any help will be much appreciated. thanks.