Several questions (assume it is a gas only tractor?): 1. Does the engine turn over when you pull it in gear with the clutch engaged? (If so, it is not "frozen")..actually check the things I have asked below before you try pulling it again; 2. When you say the starter won't turn over, is the battery charged and connected right (positive ground on those tractors); 3. Have you checked that there is clean gas flowing into and thru the carb and that the float is not stuck (also be sure that the shutoff at the fuel sediment bowl is opened): 4 If there is gas and a spark (have you checked?) have you opened the petcocks to the cylinders (they are probably under the cylinder block on your model) and when pulling to reduce the compression and make it easier to turn over (same when trying to start with starter after you get it operating)..once started, close the petcocks; 5. Have you checked to be sure that there is not water or antifreeze in the crankcase (that will indicate several possible problems).
There are probably some other questions that others will ask but this is a start!
Good luck! Great old tractor. Enjoy it once you get it going.