My understanding of using Camera RAW is that you never lose the original RAW image as shot by the camera.
I've found out the hard way that this does not seem to be true. I opened a Panasonic RW2 file in ACR 7.3 and, among other adjustments, cropped it.
Now even when I select Camera Raw Defaults from the flyout in ACR I cannot get back to the original uncropped image.
Have I lost that original for good - I thought this was not supposed to happen?
In ACR simply reset the crop by choosing Clear Crop in the cropp tool dropdpwn menu...
If you want to clear ALL settings AND crop, in Bridge you can go to Edit menu, Develop Settings and use the command Clear Settings...that's the quick and easy way of resetting an image.
If you're concearned at all about altering the original file in any way, you can apply all your ACR adjustments; than SAVE the image to a specified folder, and CANCEL out of ACR.