Acrobat X (10.1.16) used on Win 7 stops responding apx 75% of the time when I try to scroll, edit or doing nothing but click on it, after a pdf has been opened for viewing or exported from a program (usually CS6 program). The pdf's seem to create correctly. I've tried repairing the installation and as well as doing a clean install. When being used, it can also open multiple processes which have to be closed through task manager before being able to open the program again. This problem began suddenly about the middle of Dec 2015 and a second Win 7 machine developed the same issue at the same time. All updates are current. Any suggestions?