88 LS Engine lost power, overheated, now won't turn over
 

As I was driving today on the interstate, just after the top of a hill, I notice my 1998 oldsmobile 88 LS starts to ride rather roughly. My check engine light came on as I was going down the hill. I decided to pull off the freeway and check it out. The engine was idleing, but very roughly. I tried to accelerate again and drove about 50 feet, but the engine seemed to stick around 1500 RPM and 20 MPH. By the time I stopped the second time it was around 250 degrees F. I shut the engine off, and 10 minutes later, it won't start. The starter has plenty of power but the crankshaft won't turn over. Is this going to be an easy fix, or is a new engine in my future?