• Hold the power and vol down keys, and wait until the phone reboots into a screen with Android laying down with the chest open. If you get a different screen (i.e. fastboot), try with Vol UP instead of vol Down.
• At the screen that says "No Command", hold the power button, press the Vol Up key without releasing power, and then release the power button a couple of seconds before the phone reboots. This should properly enter something called "Recovery mode". Again if not, try the Vol Down instead of Vol up.
• At the Recovery screen, format the "Cache" partition and reboot. If the phone still freezes at this point, follow these instructions from the beginning again, but use factory reset instead. I have to warn you, you must know your Google account password you connected with the phone if you choose the factory reset option, and you will lose all your data on your phone.