If the AVENTHO 200 does not power on, first check that the battery is sufficiently charged. Move the power switch to the middle position. The status LED will light up red for 2 seconds and then turn off. The current battery level will be announced via voice prompt.
If powering on is still not possible, slide the power switch upward five times quickly while the device is turned on, until the status LED flashes violet. This will reset the AVENTHO 200 to factory settings.