Troybilt zero turn Model 17WF2ACP011 blade belts locked down

[Gws1590]

I have a Troybilt 17WF2ACP011 zero turn with 100+ hrs on it purchased in 2011.The lawnmower worked perfect 2 weeks ago but when I tried to cut grass today when blades were engaged choked lawnmower down. The V-Belt was off the idler pulley , after putting belt back on pulley the blades still would not turn. After inspecting mower with blades engaged noticed some sparking coming from the PTO clutch.The blades and pulleys seem extremely tight, able to push a blade and loosen V belt before tension sprocket engages. The other blades will not turn at all.Question is could it be a spindle locked down or the PTO clutch.