I have just joined this site.... love to fish EXCEPT my boat just stopped running and need help!!!

Have 2008 Triton fishing boat with 90 HP Mercury Motor 2 stroke that was bought used in April 2012. Ran great with no problems last year. Start of season this year, was spitting and choaking, brought in for service and coil was replaced. I'm not a mechanic so didn't want to play around with it. Boat ran, then more problems with choaking, replaced spark plugs, ran great. The next day after spark plugs replaced the boat didn't start, brought in for service again, now the computer went. THis was in April 2013- THIS YEAR! Now $3700 in the hole, but has been running great since the computer was replaced, no hesitation, choaking, spitting nothing. Now on Sunday, on the water, started no problem each time it was shut off as the trolling motor was being used, it's now about the 6th time and went to start it again and nothing. Everything was fine up until that point, no hesitation or sputtering.. nothing. The beep that normally sounds before it starts, did not sound. New battery was put in at the same time the computer was replaced as well, forgot to say that. Don't want to start pulling things apart, as I said before not a mechanic, but can't really afford to take it back to have it looked at for $100 an hour. Are there fuses or maybe ignition switch? Please any solutions or ideas, this boat is breaking my pocket.... thanks