Any other causes can usually be solved by restarting, resetting or restoring the i Phone to its factory settings.If none of these solutions work, you will need to take your i Phone to an Apple technician for repair.
Apple suggests a restart as a first troubleshooting step.
A restart is done by pressing and holding the "Sleep/Wake" button for five seconds.
Normally, a red slider appears on the screen, but you probably won't see it.
Place your finger a half inch from the top of the screen on the left side and then drag your finger to the right edge.
December 20th, 2011 A few days back, Chronic Dev Team member an i OS hacker Pod2g revealed a new untethered jailbreak solution for i OS 5.