Here's the step by step instruction on how to Hard Reset the LG Optimus U for US Cellular 2G and 3G network, to restore its original factory default settings.
Note: Doing a hard reset is only applicable if your LG Optimus U experiencing a hang-up, unresponsive or frozen when opening or using some application installed.
LG Optimus U Soft Reset/Factory Reset on Menu Settings
1. From the main home screen, select Menu
2. Select Settings, then Privacy
3. Select Factory Data Reset
4. Select Reset phone
5. Just enter the Password if prompted, then confirm by selecting Erase Everything
If your LG Optimus M is frozen, hang-up or unresponsive,
1. Turn it off, remove the battery out and reinsert it back again
2. Hold the Home and Volume Down button
3. Press and hold the Power button until it turns on again
4. Just follow the on-screen procedures to reset the LG Optimus U
Once the restoring process completes, the LG Optimus U will then reboot, and then it will restore back to its original default state setting again like when you bought it way back then.