See page 31 in Operators Manual, loss of drive.
Looks like your lawn tractor is 2002 year Model, see last page in Operators Manual. Remove deck & idler pulleys for drive belt & topside of deck. Idler pulleys have bearings that do wear out, try spinning pulleys by hand, any drag, noise, wobbling, etc. If pulleys are worn out or locked up belt will slip or not move at all. Let us know how it goes, thanks, Mark
Use Craftsman OEM parts.