my phone will not turn on all the way, shuts off and turns on repetitively My phone was not syncing to Google, I read somewhere to delete a file called 'etc' in my system files. I restarted my phone and found it to never turn on. It will vibrate show Samsung and then shut off. My phone is doing it all on its own and I'm not even pressing anything. I can't even factory reset because my phone will shut off before it can get to the screen. I have a rooted Galaxy-S-3 Samsung. Please help??
I hope you don't care about all your data because I don't think there is a way to retrieve it. Perhaps people with more knowledge than me know how (perhaps using ADB?). However, if you want to resurrect your phone, you need to follow this guide:

http://www.ibtimes.co.uk/update-galaxy-s3-i9300xxugnh4-android-4-3-stock-firmware-1468061

This guide below is a bit more old but you can look at it's images so it will help you:

http://forum.xda-developers.com/galaxy-s3/help/guide-odin-flash-guide-t1671969

The first guide will help you flash a 4.3 stock ROM to your S3 to revive it, but please make sure it's model is GT-I9300!!! If you have a Verizon or any other variant you may risk bricking your device.

Good luck.