try removing the battery while it's still on. then put the battery back on and turn it on. if it still doesn't work, contact your wireless provider. if you've had it under a year and it doesn't have any water or physical damage, they will replace it for you for free ( warranty). if it's been over a year since you've gotten it, ask to see if you have insurance on it. if you do, they will replace it for you but you have to pay a deductible. the price depends on what company you're with.