1In large bowl, mix beef, soy sauce, 1/2 teaspoon of the gingerroot, the green onions and garlic.
2Spoon beef mixture by rounded tablespoonfuls into 10-inch skillet. Cook over medium-high heat about 6 minutes, turning occasionally with spatula, until beef is no longer pink in center. Remove beef from skillet; keep warm. Drain drippings, reserving 1 tablespoon.
3In same skillet, cook remaining 1/2 teaspoon gingerroot in drippings over medium-high heat 30 seconds. Add bell pepper, red onion and bok choy. Cook, stirring occasionally, until crisp-tender. Stir in teriyaki sauce.
4Return beef to skillet; cook until hot. Meanwhile, cook and drain noodles as directed on package. Serve beef mixture over noodles.