Uninstall Reader using http://labs.adobe.com/downloads/acrobatcleaner.html
then download and reinstall it from http://get.adobe.com/reader/enterprise/
If the crashing and hanging persists, disable Protected Mode via the registry: download, unzip, then run the registry script from https://files.acrobat.com/a/preview/06befba0-92aa-4996-bced-587054e0cf26