Have a murry riding lawnmower and will not move... put brake on and we can still push around.. anyone kowe what to look for ? Was moweing and moveing fine and then just stopped moveing ! Belts fine .trnsmisson spining..?

Hi,
Only one thing comes to mind that would cause the situation if these are all the facts (and I am suspicious that they are) and that is the plastic backside idler in the drive system has seized and the belt has melted it to the point where it does not properly tension the belt.
The brakes can be adjusted with a 1/2" wrench on the right side and has nothing to do with this.
To check the health of the transaxle, place in gear without engine running and try to push. It should move a little in both directions.
Peace,
Clarke