I'm glad to see I'm not the only one having this problem. I have four PCs running Window 7 Home Premium. My three 32-bit systems took the 5.1889 update without a hitch, but my 64-bit system is experiencing the same problems stated here in this thread. I am running Threatfire, and I think I would switch anti virus programs before uninstalling Threatfire, if that program is even the one causing conflict. Has anyone been able to determine if Threatfire is the culprit?