Turn off the Xbox 360
Unplug the power cable
Wait 30 seconds
Plug the power cable back in
Turn on the Xbox 360
To reset the console settings, go to System Settings
Select Console Settings
Select System Info
Press Y, then enter the button sequence to clear the cache if needed
To factory reset, go to System Settings
Select Storage
Highlight the hard drive
Press Y
Select Format
Confirm the reset
To reset a frozen console, hold the power button for 10 seconds
Turn it back on after it shuts down