Master Reset. Do a format via Recovery Mode. To Enter Recovery Mode. 1. Turn off your device 2. Hold Volume Up + Home + Power until on the top left corner of your screen displays blue text 3. Format via Recovery This will reset your device back to factory settings and hopefully flush out the culprit draining your battery life.
If your device is rooted, there are various apps you could run to remove the screen lock. Root it, enable adb on your device so your computer could recognize it and attempt to unlock it. Otherwise just perform a hard reset via recovery mode on your 1. When the phone is switch off , press and hold the VOLUME DOWN key + POWER key with your left hand. 2. When the LED on the bottom of the phone lights up, touch and hold the MENU key with your right hand. You need to do this immediately, before the screen displays the LG logo. Make sure your left hand is still holding the VOLUME DOWN and POWER keys. 3. Then release the POWER key at vibration time. 4. When the LG logo is displayed on the screen, continue to hold the keys for around 2 seconds, and then release all them at the same time, before LG logo disappears. 5. Leave your phone for at least a minute while the hard reset is carried out .You will then be able to switch your phone back on. CAUTION: If you perform a hard reset , all user application and user...
If you want to fully repair your device, I would definitely recommend it. You don't have a dust issue, the screen will feel more "firm". And I personally believe that with the gap filled up, your phone will withstand minor flex and prevent another cracked glass. With that said, due to the labour and skills involved and since it's a S3, do you really need a 95% repair ? Or would a 80% repair be suffice ? Your call on this =D
The temperature sensor may be faulty ? Try installing a Fan Management App. http://www.macupdate.com/app/mac/23049/s... This will give you control of your fan speed but more importantly the temperature of your CPU. Maybe it just needs a good cleaning to ensure it's cooling down properly.
You probably have a sticky "Power Button" I haven't teared one down but based on experience it's probably using a "dome" button on the side. If it is. Open up the phone Heat up the power button slightly Peel the orange sticker back to expose the metal dome Clean it and reassemble. If it's a "push" button; White tab that clicks into a metal assembly, you will need to resolder a new button onto it.