Preheat oven to 350. In a large skillet, brown ground beef, onion and bell pepper. Drain and return to skillet.
Add tomato soup, cream of mushroom soup and garlic to skillet mixture. Heat through. Add 1/2 cup of cheese and stir till melted and blended thoroughly.
Combine skillet mixture with cooked spaghetti until blended thoroughly. Pour mixture into a 13 x 9 casserole dish. Sprinkle remaining 1/2 cup of cheese on top. Bake at 350 for 30 minutes. Should be bubbly when time is up.