Advise on my JD STX38 TRACTOR

[JD TRACTOR MAN]

I just purchased aJOHN DEERE STX38 TRACTOR which I really like. However I just got it a few days ago and went to start it the next day and it would not start. I trouble shooted it to the starter and also installed a new battery because it was on its way out. Installed them and it started right up. The next day went to cut my grass and It starts right up and runs good but went to engage the blade to cut the grass and it is not cutting the grass. Checked the belts and there ok Everything else seem to be ok.NO LOOSE CONNECTIONS, does anyone know what it could be? IF anyone knows what else I could check out that I might have overlooked please contact me direct @ IAMDESPERADOJDD@GMAIL.COM Also I really like this tractor but has anyone ever owned this model or know of someone who did and let me know what you think of the JD STX 38 MODEL. THANKS JD TRACTOR MAN