Is it legal to sell a computer game developed using Microsoft Excel?

My husband created a popular games' scoreboard that eliminates the need for paper and is a lot of fun. It is created in Microsoft Excel, therefore eliminates the need for paper, computes scores and has many possibilities including the use of avatars and sound to make it fun, and therefore marketable online. I am aware I cannot use the games' logo's or title. I have researched the Microsoft website, found freeware that simulates excel, but still don't know the legalities of the use of Excel or the like.Do you developers or others know the answer, or have any advise or alternative suggestions?