This happened to me to!
But the problem I'm having is when I put the Samsung tablet 7.0 on charge it comes up with the loading symbol then the charging symbol then the screen turns black and then back to the loading symbol again, this goes on forever no matter how long I charge the tablet and how many buttons I press to try to turn it on it just won't.
I read up on it and looked on YouTube and people actually removed the back of the tablet and take out the battery leave it for an hour and then put it back in, this sort of resets the tablets battery yet doesn't remove any files or anything you need on the tablet.
If you look up on YouTube "How to remove a battery from Samsung Tablet 2" it should come up with a series of videos showing you the safest way possible to do so, if not just go to the store and get it checked out, or you get them cheap Indian repair shops on the corners in places in London who would happily do it on the spot and for cheap and maybe even tell you what's exactly wrong with it as they might have come across it before.
But please if anyone does find a easy, quick solution to this problem let me know.