My trimmer died, and will not give spark?

I have a model 825r Ryobi gas trimmer that I have not used for 3 years. When I first tried to start it it fired once and now will not fire even once. I have replaced the spark plug and made the proper gap, but still no luck. Anyone with an idea?
I have only used this unit 5 or 6 times before I cleaned out the gas and put it up.
A neighbor needed the extra work so I hired him for my lawn care. He passed away in March this year from cancer, so I will be working in my yard again.