On the crop tool's option bar, top left, there is a little arrow. Click on that, and reset the tool.
On the most recent version of the program, the reset button is said to be somewhere at the bottom. We don't know which version is on your machine.
If you have PSE 11, click the four-lined square at the right end of the tool options area.
Thanks so much! Such a simple solution to a problem that caused me so much consternation.
Sent from my iPhone
You're welcome. Glad to hear that it's fixed.