pat, not knowing anything else about this mower except for it has a broken 5" spring, I can say someone can repair the mower, maybe even you. But you gotta know where the spring came from. My guess is that it is the tensioning spring that keeps your drive belt tight. Without the spring in place, the drive belt is just slipping. But it also could be as complex as maybe the drive belt broke and snatched the spring out by force.
If you post the full model numbers of your mower (find the decal under the seat or near back of mower usually) someone on the forum might even be able to give you some part numbers. In the mean time try to see if you have 2 belts on the engine crankshaft. One for the deck and one for the trans.