Hi,
This update can be stopped thru Task Scheduler.
Please try the following steps.
Click your Start Button, type Task Scheduler and hit enter
In the left Panel, navigate to: Windows - Update Orchestrater
Right Pane double click 'Update Assistant'
Click on Triggers Tab
On each of the triggers ( At login . . . etc.) double click and uncheck 'Enabled'
Under 'Update Assistant, there is another event 'Update Assistant CalendarRun'
Hope this helps,
Mark