Dredge beef in flour and salt. Melt butter or margarine in large skillet and add beef and onion. Cook over medium heat until browned. Place beef bouillon, ketchup, garlic and mushrooms in crock pot and mix. Add cooked beef and onions. Cover and cook on low for 3-4 hours. Add sour cream, cover and cook for 30-45 minutes (do not let mixture boil). Serve over hot cooked noodles.