John Deere X748 won't start. Any ideas?

[EMailau07]

My John Deere X748 mower won't starting, no cranking. Installed new key switch and relays but still won't start. When the key is turned, "Prog 1or PRO9 1" is displayed. Battery is at 12.75V. Fuse is good. Oil is good. Got fuel. In my opinion, its the starter but I'd like your options.

 

[slomo]

When was the last time the valves were adjusted?

Look for bad grounds and mice eating wires.