Tools, Sharpening and Power Machinery - Air Compressor not running

I have a 5 year old Craftsman 25 gal. air compressor that has decided it doesn't want to run anymore. It kicks the breaker just after it starts up. I thought maybe the breaker was bad so I tried another circuit...same thing. I then thought the starter capacitor was bad so I replaced it ($39.95 at Sears.com). That didn't work. It still kicks our the breaker and won't build pressure. Any thought? Any ideas that would help me figure this out. It is not locked up. The fly wheel spins easily with the finger. HELP?????

Does it have oil? If the piston's dry, I think it'll take too much effort on the motor's part and over load. Not an electrician, just a guy with old tools who has to limp along at times.

If it is belt driven,take the v-belt off and try it to make sure it is a motor problem. Take the cover off pressure switch and check condition of contacts. If it still trips, I'd take the motor to an elec motor shop to have it checked.
Mike