Noticed this happen about 2-3 times since I got the phone on launch day... In fact, it just happened again. Was wondering if anyone else had this problem. I've noticed sometimes when I leave my phone alone (standby, screen turned off, etc) and try to wake my phone, the phone does not power back on at all. And yes, battery still has a good amount of charge left. I can press the power/wake button but no response. No unlock screen, nothing. I hold the power/wake button and it does not boot either. Only a battery pull will allow the phone to boot go back to normal again. Anyone have this problem before?