smelling a burning smell upon starting

Can't smell it over a computer so I can't tell if it's electrical, engine oil, or coolant. Have any fluid levels been going down? Do you see any wetness on the engine or on the ground where you park? Be sure the rubber seal is in place at the rear edge of the hood and there are no gaps in it.

The car is stone cold when starting it. It has been in the 30's here in the morning when I leave for work.That is when I smell it. There is no oil leaking, I do have a crack on the hose mount on the radiator, there is a coolant leak, but it doen not leak onto the motor. I see no wetness on engine. When driving, the car has been chugging when accelerating until it gets warmed up some. Upon looking at engine, the tension pully for the serpentine belt seems to not be rotating. Now this morning (Jan 10th)my car wouldn't start. The engine turns over but fire. Also could you please tell me where the fuel filter is located? The smell is like what a firework would smell like after it has gone off and picked it up and smelled the burnt firework. That is the best way to describe it.

The fuel filter is usually mounted to the right frame rail. Here's a photo from rockauto.com to show what it looks like.

Idler pulleys often look like they're not turning because of the shiny black paint. It's easier to tell if there's a little dirt on it. You might consider sticking on a piece of tape or a wet leave, . . . anything to make it easier to see. Some designs include a large diameter stamped steel disc under the center bolt that does not spin. You have to look at the part the belt contacts. If the belt is indeed sliding over a locked up pulley, you should be hearing a severe squeal, have intermittent loss of power steering, or some other symptom. The belt would definitely start to smell and overheat. That smell would migrate into the vehicle after the engine was turned off.