Not sure if this is coincidence or is actually related to the recent Android update. My Galaxy S3, ever since the update, will have the power button not work to shut the screen off. It won't shut off on its own either. I've had it to the local Samsung Experience center at Best Buy where they reinstalled the software and did a factory data reset 3 times. Right after all of that the screen will shut off with no problem, but after 3 or 4 days of having the phone shut off most of the day at work and turning it back on later in the day it will start acting up again and I can't shut the screen off. Also happening at the same time is failure to connect to wi-fi - won't go past the checking of the wi-fi signal - won't connect. I've not installed any apps on it after doing the reset and it will work for 2 or 3 days after doing the reset but then it's back to the screen not shutting off. It's been sent to Samsung once already for repair but all they did was reinstall the software, at which time it will work properly and then they send it back to me. My warranty is good until November. Samsung says they do not replace phones, just repair them. I am sending it in AGAIN to see if they can repair it. The Samsung people at Best Buy said it is definitely a hardware issue. I'm betting they will just be reinstalling the software again this time, too. Anybody have this issue? After the Android update? And wth is up with the no replacement/only repair at Samsung??