Skillet Sketti

1 pound lean ground beef
1/2 cup chopped onion
1/3 cup chopped green bell pepper
1 clove garlic, minced
2 teaspoons salt
4 cups water
1/2 pound spaghetti, broken into 2-inch pieces (about 2 1/2 cups)
1 (14 1/2 ounce) can tomatoes, cut in bite-size pieces
3/4 cup ketchup
Grated parmesan cheese

In large deep skillet sprayed with nonstick spray, saut