Hey guys I made a small game over the last week.
Your goal in this game is to swipe over the screen and collect all grey dots. But if you collect a red dot or if your time runs out, you lose the game!
Install Google Usb Driver if not already done (http://developer.android.com/sdk/win-usb.html) and if you use windows 8 follow these steps (http://stackoverflow.com/questions/21972658/adb-driver-and-windows-8-1).
If that all doesn't work, I am out...
I guess your usb cable works and your computer recognizes your device? If so, take out the battery of your device for a few seconds, start it again, connect it to your pc, type in 'adb kill-server' then 'adb devices' and look if it works.
What exactly doesn't work? When you connect your device to your pc and type adb devices in cmd, what does it show?
I think this might help http://www.technobezz.com/flash-stock-rom-via-odin-samsung-galaxy-s3/. If you have access to the download mode, look for the stock rom for your phone and try out the tutorial.