Drove through the drive thru and my car shut off?

I have been talking to a mechanic through you guys for a few weeks now and I am a person who prefers to speak to one who is aware of the problems I am having with my car. But as I was asked to do, I will do it for this problem. The other day I started my car and went to the laundry mat, which was there for a couple of hours. Started it again and drove it home and about 2 blocks and it was idling at the light for a couple of minutes then took off went through the drive thru at McDonald's and went to leave and my car shut off. I have to start my car by taking off the positive cable for 2 minutes to override the anti-thief system. Well sometimes it takes a few minutes, but I have to just let it set. But what my question is, why would my car die when the fan stopped running. When this happened, I had to move my car off the street at my apartment complex into the parking lot. My car had been sitting for a few hours by the time I moved, but I noticed it was idling rough and as soon as I put it in park the fan was running from the start and when it turned off the car died. What could be the cause? The fan was a bit loud plus it wasn't coming on every time the car ran and it has not overheated, not once.