Here is an actual solution which will 100% work.
First get to your Task Scheduler.
Start -> Control Panel -> Administrative Tools -> Task Scheduler
Next, Navigate to the Task Scheduler Folder
Microsoft -> Windows -> Task Scheduler
Right Click on "Regular Maintenance"
Select Properties
Go to the Settings Tab
Check "Allow Task To Be Run On Demand"
Click OK
You can now manually start and stop maintenance...
Right Click on Regular Maintenance, select RUN
Right Click on Regular Maintenance, select END
Basically this will run a new instance of maintenance and stop all currently running instances.
End will stop the current instance you have started. You should no longer have it running at all.