I was looking through the Google Play Store after I rooted my LG Motion 4G The other day, and came upon the app "Beats Audio Installation" & Downloaded it and then when i opened the app and finished the setup, it started Rebooting and you cant go to your regular screen, etc. You can only see the Metro PCS logo and LG Logo in the beginning and it keeps rebooting. Please Help!
You could try booting into Safe Mode (according to this article you should be able to do so by holding down the Vol - key while switching on the device with the Power button).
In safe mode, all user-installed apps are "disabled", so they won't be started automatically. Once in safe mode, remove the troublesome app (uninstall it via Settings → Applications → Manage Applications). Then simply reboot to leave safe mode -- your device should now boot up fine.