My mower is only 2 months old. I went out today and it started fine but it would not go backward or forward. I tried locking/unlocking brake, turning mower off and pushing the mower. I pushed pedals with mower off with my hands. Still nothing. There is nothing in the manual in regards to this situation. The mower has been in the garage since I mowed last week. There was nothing unusual about the mowing. Help me please.