2000 Ford Contour - Stalled while driving - Wont start

[phameus]

00 Contour SE 2.0 VCT 140k miles.
- may 2009 timing belt idler pully replaced
- Car has been using excessive amount of gas for a few months now (prior to the timing belt issue)
- CEL is on - I cant recall the actual code but its for the catalytic converter.

My girlfriend was driving home from work yesterday and heard a single "pop" sound from the engine of her car. The car continued to drive perfectly for approx 5 more miles then the oil light on the dash came on and then the car suddenly died. She called me and I told her not to try and start it or do anything else.

When I arrived to come pick her up and have the car towed I lifted the hood and didn't see anything out of the norm so I had her try and start it. I immediately noticed that the cam gears that the timing belt is on were not turning while the engine cranked.

She only attempted to start the car once while I was there and she did not attemp to start after it died before I arrived. So it was only cranked one time.

I am kinda concerned about the noise that she heard but I am not sure where to start because the car continued to run fine for a while after she heard the noise.

Any clues?