So I was holding back on updating to 4.4 for a while now and finally did it yesterday. Once installed, I started noticing problems immediately. Screen not unlocking(taking 45 seconds after pressing the button), lag and severe overheating. I read on another thread that uninstalling the Device cleaner, antivirus and battery saver apps was the remedy, which I did and it worked. After waking up this morning, the device is near to unusable. The wifi won't connect at all, overheating again and the screen just will not *lock. I can open the the power off menu by holding down the lock button, but the screen just doesn't go off. I changed the time required for inactivity for it to shut off itself to 15 seconds, left it idle, yet it still didn't turn off. I'm getting REALLY frustrated guys.