My phone won't turned off it locked up on me
Lock up again
Just hold down the power button for about 10-15 seconds. It will turn off and reboot.
However, if you must Hard reset to factory settings try this instead.
Plug into charger for the entire process
Charge to 100% and back up and factory reset the G2
(DISABLE google backup and restore of apps and app data in Backup and Reset screen)
Factory reset one more time
Unplug from charger
Set up your phone
Leave G2 on until it dies and turns off 1 time
Leave off and recharge to 100%