Use o Powershell!
Disable-ScheduledTask -TaskName "Adobe Flash Player Update"
TaskPath TaskName State
-------- -------- -----
\ Adobe Flash Player Updater Disabled
EDITAR:
com o uso de schtasks.exe:
schtasks.exe /change /tn "Adobe Flash Player Updater" /disable
SUCCESS: The parameters of scheduled task "Adobe Flash Player Updater" have been changed.