usually when i turn my acer tablet on it comes up with a black screen with the acer logo in the middle then goes to another black screen with the blue android logo. The acer logo screen lasts for about 20 seconds. when i turn it on now the acer screen stays there for ever until it runs out of power. i have tried draining the battery then starting it up again but it didnt work and im really worried. can someone help me? [i am going away in 2 days so please help me before then.]