The battery of my Galaxy Tab 7.7 (p6800) was exhausted and it turned off. After I plugged it in, the battery indicator came up but no charging status was shown and when I turned it on, it stops at the "Samsung Galaxy Tab 7.7" page! what should I do?! :(

P.S.: I tried to use recovery menu options to clear my cache by pressing volume up key + power key, but nothing goes up!