Dodge Dakota Engine Locked Up

I Drove To Work, Locked The Doors With The Key Fob. At Noon, I Took Something Out To My Truck. The Key Fob Wouldn't Work, So I Unlocked...

Over The Course Of Three Days Engine Continued To Heat Up Then Cool To Regular Blow Cold Air. Finally Engine Overheated Began To Shudder....

I Recently Bought A Used 1998 Dodge Dakota Pickup For $3000 From The Honda Dealership,i've Had It For About Three And Half Weeks I've Been...