Help!! How can I get my gas BBQ grill to work again?

I have a BBQ grill that is about 2 yrs old and uses propane. I haven't used it for almost a year now and I tried to start it the other day bug does not work anymore. There is no sound of propane coming from the the grill when I turn on the knob. The propane had also been refilled. Is it clogged somewhere in the gas wires? If so, how can I fixed this? Can there be any other problem if it is not clogged? Thanks!!