welcome to the forums!
try this, i had the same problem you did
if you get this phone exlamationpoint computer screen, a ''soft brick'' try this method
1. Take out battery, put it back in. (to turn the phone fully off)
2. Don't turn it the phone on!
3. Plug the phone into your PC, do not hit the power button!
4. See if the phone shows anything on the screen (powers on its own when plugged in)
IF the phone screen does 'turn on' after being plugged in without you hitting the power button, so far so good.
5. Now while it's on like this, hold the volume up and volume down buttons.
6. Hold the power button as well as the volume buttons until the screen goes black.
7. As soon as the screen goes black, let go of the power button! But DON'T let go of the volume buttons!
you should then be back in to download mode. ODIN AND ENJOY!