Moved mower out of shed to sharpen blades, moved fine. now it won't move forward or in reverse. belt is workin, fan on rearend is turning, but mower won't move. the break is workin the rotor thing, but not engaging to the rearend.

Lift left hand foot pedal to full extent with top of foot may find that it is not engaging idle pulley, may be time for a new drive belt

These units use Hydraulic pumps for motivation. If the unit stopped all at one time, I suspect a drive belt came off.
For both pumps to fail at the same time would be very odd. Check the v-belt driving the wheel pumps.

I would lower the deck to the lowes setting and look between the frame and the deck toward rear wheels and check the drive belt it sounds like it is slipping or busted.

The forward reverse pedal linkage needs adjustment. Remove mower deck pins and slide out of the way. Pull linkage pin out then turn clockwise one full turn .move brake pedal while looking at it .You should see a small brake disc on side of rearend with a nut bolt going through the disc. Pull rod on back of mower that allows you to push mower freely.set parking brake try to move mower by pushing if it moves with break set tighten bolt that goes through brake disc til mower don't move.release parking brake try to move mower should roll easy.if not losen bolt 1/2 turn til it moves easy.reengauge rod on rear of mower to drive it test and be sure to place cable ties on any thing under mower dragging ground .If test works .reinstall mower deck.

You need to check the belt to the hydro units is connected properly and is tentioned and not slipping in the pilleys

Confirm the park brake is off. If a hydro-static drive tractor starts but engagement of the operator controls for the transmission drive results in neither a forward or reverse drive of the mower itself, the operator should check that the manual bypass controls have not been left in the activated (bypass) position.

Look in to where the lever connects and confirm the movement. You should be able to hear the hydraulic oil with a slight whine as you activate the drive forward pedal!
See page 18 for bypass setting?
Cut and paste link
http://www.troybilt.com/wcsstore/TroyBiltUS-CAS/Attachment/ownersManuals/riders/HorseXP_2012_769-07569[1].pdf

I had a similar problem with my TroyBilt 50 inch zero turn mower. Was cutting grass when it stopped going either forward or backward even though it would start and the PTO would move the cutting blades. Turned out the tensioner spring for the belt that drives the motors near the rear wheels had gone missing. Searched the yard where I had cut and moved the machine but couldn't find it. A new one cost me about $7.50. Put the new one on and it worked fine.

could be engine timing not right

Hello
Check on the mower that your drive belt has not come off or has not broken
Thanks

hello otto i would check the belt that runs to the rearend but the brakes could be also froze up i would try to jack it up & see if it will move then go from there