I saw a trailer for a movie back maybe around 1983 - 1988 about a guy who wakes up one morning and all the people in the world have dissappeared , he wanders about the world wondering where everyone has gone... does anyone know the name of this movie? It looked kind of scary ?

It may be "The Quiet Earth", which I just got through watching. It's from 1985, filmed in New Zealand, and the basic plot is that a guy wakes up one day and everyone is gone. He doesn't wander around the world (he is in New Zealand, after all!), but does wander around the country, trying to find out what happened and if there are any other survivors.

Just an fyi: It's R rated, and has full-frontal male nudity.