Most likely your motor has been damaged.

You can test the ESC as follows: Take the propeller off. Using a voltmeter, check the voltage coming out of the battery. Then check the voltage at the motor where the black/red wires are attached with the control at full throtle (the motor will run). If it delivers the full voltage provided by the battery then the ESC is working properly.

By the way, these motors are cheap. I think Parkflyers.com has them for $19 for a set of two.

Hope this helps.