wideH2O

My 9-3 won't start. The engine cranks and all of the electronics appear to work, but the engin just won't turn over. Before I have this thing towed to a mechanic, does anyone have any suggestions for things I should look for? The car worked perfectly 45 minutes before I couldn't start it. I thought I smelled something burning when I got out of the car.....how do I check if the clutch needs to be replaced? This is a 5-speed, by the way. Thanks.