might chk to see if your park brake mechanism located on on the tranny is stuck... a cuppla shots of rattlecan brake cleaner will help that.
Get your battery LOAD tested and while it's out, clean all related electrical connections to bright metal with sandpaper or such, including chassis ground points.
Look in the body cavity under the tilting seat seat for a decal with the full model number - post back here so we know which machine you have.

Thanks for the info..brake is not the problem. It is working also if depressed. Battery connection is OK. Battery has lots of power. Engine will not run over because the unit is in gear! I can't take the load off the engine. Make is MTD Model is 13AM6736500 Manufacture date was early 2001
Thanks

So is the problem that the engine won't start or that you can't get it in gear or you can't get it out of gear? You said the rear wheels were free to turn then you said it was frozen as well and couldn't move?

I think you need to take your problem elsewhere, as our advice doesn't meet your expectations. sorry.

It would be entirely possible for the main gear box of the tranny to be frozen or seized without having any effect on how the wheels rotate when lifted off the ground and turned by hand.
If the wheels turn in opposite directions that only indicates that the DIFFERENTIAL section of the tranny is still free.
You say the brake still works..............how would you know? According to your report, you have not been able to move the tractor.
A frozen brake does not mean your brake pedal does not move......it means that the brake CALIPER and/or BRAKE PADS (pucks) are frozen/stuck and will not let the transmission brake shaft turn.
Does the engine not make any kind of noise when you turn the key? Total silence?