Weird Sound Issues.

Hello,
I did the big update two days ago and all went fine, like it. The only thing I really did was put all my apps into files. I was using my iPad last night at first it was ok but then picked it up again an hour or so later to play a game and there was no sound. Checked the game settings and that was ok, tried other games and they too had no sound. Played iPod and I can hear my music, tried some online videos and I can hear them ok too. Checked my mail and there is no sound in Mail, no ta da as the mail arrives. Also as I type now there is no sound, no tap tap. I did a search and checked the orientation button, that is fine. How come sound works in some places and not others? I'm not too Techy, any help would be greatly appreciated. Thank you.