Just thought I would share my experiences this morning as I could find no help myself when trying to resolve. After the server installed the update kb982526 over the weekend I noticed that the zcm admin page wasnt loading. Logged into the server and it was asking for a restart after updates (strange since its set to auto restart over the weekend for updates) so i restarted.

After the restart I could not remote desktop (showed empty desktop and tried to login then gave up) in so remoted directly to the server and logged in and it too AGES to login and was doing some really weird stuff. Running the ZCM services manually gave the error 1069 The service did not start due to a logon failure. It turns out that the zenworks account __zz_123_1__ or something similar was no longer given the rights to run as a service as pointed out in the Event Viewer. After putting it back in to this security option all my issues went away (2 hours of downtime later).

Hopefully this helps someone in the future.