Tiny 6410 Windows CE 6

I use Tiny 6410 with Windows CE6. 

This device is install at outdoor within a chassis. 

I have develop a software program and run at 24 hours operation.

However, Tiny 6410 will hang once a while within few days or within few
weeks time. 

During it hang, the LCD monitor totally no display output but the power LED
indicator still on. This condition will recover after do a power reset.

Does anybody face this condition before and any advice for me please?

Thanks.