Your registered publisher name and everything about your app—name, logo, description, screenshots—must be unique and free of Microsoft trademarks unless (1) you’ve secured permission from Microsoft through a license or equivalent (though such licenses are not generally available in this context); or (2) you’re using a Microsoft trademark (not including logos) to describe your app’s features or functionality without suggesting that the app is actually published by Microsoft. The name of your app, however, cannot begin with the Microsoft brand at issue. In addition, Microsoft logos cannot be used as a source identifier for your app, including but not limited to, your launch tile image.
For example, you cannot name your app “MSN” or “Windows Media Player;” however, it would be acceptable to name your app “Reader for MSN” or “Media Player for Windows” as long as you do not use the MSN or Windows or Windows Media Player logos or otherwise suggest that the app is published by Microsoft. Additionally, language like "works with," "designed for," and "optimized for" are all acceptable terms to explain that your product is designed to work in conjunction with a Microsoft product or service.