04-22-2014 04:53 PM
If you mean that you can't access the phone because there's a password on it, simply enter any old password on ten attempts in a row. After that many failed attempts, the phone will wipe itself of all user data and will be unlocked and ready to use.
If you mean that the phone is accessible but when you type something it doesn't show up, simply take the battery out while the phone is powered on then replace it a few seconds later.
I hope that helps you.