I'm going to save some time here and eliminate the next three messages with a single message. I hope you don't mind.
It ran very well until today? What happened today?
"It stopped running!"
Thats interesting.. Did anything unusual happen wehn it stopped?
"No, it just died"
Did the spark plug wire fall off?
"No, it didn't"
Can you provide some clues that might help diagnose the problem?