Samsung Galaxy S2 / Epic 4G Touch - Soft reset
To soft reset your phone press and hold the Power/Lock button for a 2-3 seconds and the phone will restart. Wait about 10 seconds and then press and hold the Power/Lock button again to restart.
If that doesn't work, then remove the battery. Wait 30 seconds and put the battery back in. Then press the Power/Lock button to turn the phone on.
We have 95 tips for the Samsung Galaxy S2 / Epic 4G Touch.