How can I fix my MTD Yard Machine ?

Hi ,
I have a MTD Lawn Tractor that was given to me . It has been a headache ever since I've had it ! Its only worked once . The engine would run fine but would not go into gear ! The blades worked fine though ! So, I had a knowledgable person help me with it and he ended up replacing the drive belt , one end of which fit on a front pully underneath the engine (not easily of course) . So, it worked one time last fall and after that I let it sit all winter. I went to start it the other day and the engine started perfectly ! The engines the best part about this tractor. But it won't go into gear to get it out of the garage; Forward or reverse ! No wonder it was given to me ! Short of spending a few hundred on fixing it; is there an easy thing to look for ? Or is it worth fixing at all !