system not found acer tablet a100

Hello acer forum, I' m really exhausted to serch on the web for solutions about my problem so I' ll explain it: I have this tablet and it doesn' t work, it bricked itself, when I start the tablet normally it stops in the android logo when it's charging the system, when I start it in recovery mode 2 pictures appears the first with an android that is charging something and the second with the same android lying with stomach opened with a ! inside,the recovery mode is not working because any option show in the screen,There is no possibility for installing the system from sd .please help me .thanks