Drug-store chain Walgreen Co. is reversing a roughly 15-year-old alcohol sales ban by returning beer and wine to its shelves.The Deerfield, Ill., retailer is hoping offering alcohol will boost its sales and market share, making it a one-stop shop without affecting its community-friendly image. Up until the mid-1990s, most Walgreen stores had full liquor sections, making the chain one of the nation's largest liquor retailers with liquor and other beverages comprising about 10% of total sales. It quit when the stores' liquor sections became cumbersome to staff and time-consuming for store managers to maintain, said Walgreen spokesman Robert Elfinger.