If your riding mower isn't going forward or backward, there are a few things that could be causing the problem. The first thing you should check is the transmission. If the transmission is in neutral, the mower won't move. If the transmission is in gear, but the mower still isn't moving, the problem could be with the drive belt. The drive belt could be broken, or it could have come off the pulleys. Another possibility is that the wheels are locked. If the wheels are locked, the mower won't be able to move. Finally, there could be a problem with the engine. If the engine isn't running, the mower won't be able to move. If the engine is running, but the mower still isn't moving, the problem could be with the carburetor, the spark plugs, or the fuel line.