Well, the clear flash tool wouldn't cause any loss of data, or shouldn't.
According to TomTom vernacular, a 'hard reset' refers to restoring to factory defaults. While that will cause a loss of custom settings, it won't erase the map. (A 'soft reset' is doing a pin reset for models with the reset hole and holding the power button for about 20 seconds for those models without). And a 'soft reset' will cause only the set time to go back to 12:00 in many cases, no other data is lost.
So, there is certainly more at play here.
If you connect your unit to the computer (Not Home), do you see anything on it using Explorer?