Several things can cause the mower to not move when you push the forward pedal.
You might have a broken or loose ground drive belt.
The linkage from the pedal to the transaxle might be bent or loose.
The transaxle might be bad.
The "free wheel" lever might be pulled out.
The brakes on the tractor might be stuck.
It might be best to call 1-800-469-4663 or go to
and schedule service for a Sears technician to diagnose and repair the problem.