I have seen references online that state that \'Scheduled Tasks\' in Windows are stored in %SystemRoot%\\Tasks, which I think usually equates to C:\\Windo
I want to extend @Jan answer:
It's seems, that Task Scheduler 1.0 API uses C:\Windows\Tasks folder for create and enumerate tasks (this example), while Task Scheduler 2.0 API uses C:\Windows\System32\Tasks to create and enumerate tasks (this example).
It's also seems, that windows console utilite schtasks and GUI utilite taskschd.msc uses Task Scheduler 2.0 API.
P.S.
I found, that if task placed in C:\Windows\Tasks and have not setted AccountInformation, then task won't be displayed in windows console and gui schedulers. If you set AccountInformation (even "" for SYSTEM account) and set flag TASK_FLAG_RUN_ONLY_IF_LOGGED_ON - task will be displayed in all standart applications.
Solution found here