2000 Ford Escort Engine turns but won't start

2000 Ford Escort 4 cyl Manual 170000 miles

My 2000 Ford Escort Sedan started and drove fine in the morning. Later that afternoon, the engine would turn but would not start. The battery seems fine - the radio, lights, horn, etc. All work fine. However, when I turn the key to start it, it seems like it wants to start & makes a reving type noise, but it won't go. Could this be a problem with the starter, the distributor, the sparks plugs, or what? Please help! Thanks!