What’s the difference between Skype for Windows RT and Skype for Windows desktop?
If you’re on Windows XP, Vista, or 7 you can use Skype for Windows desktop. If you're on a Windows RT device, you can use Skype for Windows RT.
Skype for Windows RT is optimized for your Windows touch-screen device and is always on, allowing you to keep in touch with your friends more easily.
Both versions allow you to sign in with your Microsoft account, so it's easy to talk to your Messenger contacts. Learn more about Microsoft accounts.