My central air unit outside humms continuously like something is going to happen but the fan does not turn at all. The inside fan from my furnace is blowing cool air but not the cold air you would expect from the AC. I flipped the breaker off/on on the inside fuse box and on the outside switch located near the AC unit (no idea what this switch is though). Nothing. The temp in the house will not drop (set well below the current temp).

Before starting it the other day for the first time since last summer, I cleaned it with a garden house. I turned it on later and saw a big spark go off at the top. So this probably has something to do with it (scary sparks=bad) but a heating guy told one time that this cures most of the calls he goes on ( I failed to ask whether the breaker should be turned off, which I did not do). To sum up, I probably broke it, but just wondering if there is something a amateur could do himself.

Thanks,
Kevin

At this point I would call for professional service. A spark is not normal and indicates something shorted out. (probably got wet in the cleaning.) DYI can sometimes cause a problem if you really do not know what you are doing. Good luck.