My touch to unlock screen does not work.My battery was dead and then i put it on charge.Later when i turned it on it did not work anymore,although the screen turns on and is perfectly alright.PLZ HELP :(

i dunno the same thing has happen to mine 2nd generation.I dont know why but the battery was dead and i put it on charge and it does not work.it happen 2 times already.Now is the 3rd time PLZ HELP;(