Craftsman riding mower started for the first time this season. Made one pass around the yard, shut mower off for less than a minute. Tried restarting and the only thing you hear when turning the key is an electrical type of grinding noise. Mower is 12 years old and have not had any problems at all. Thanks for your answer to the starting problem!

Souinds like the starter bendix is bad. The bendix is a candycane like shaft with a gear on it that flies forward and slames into the flywheel. This gear is the weak spot of the system and is designed to fail before more expensives parts break. Remove to starter to inspect.