Can someone please tell me what font/fonts Microsoft is using in this screenshot? I have tried several of the online resources supplied in the guidelines about identifying fonts, but the results are definitely not correct. I am not a designer, so I really don't have a clue.
It is indeed Segoe UI, as God is good answered. This is the main font used by Microsoft since Windows 8 was anounced in 2012.
If you want to discover fonts names from screenshots, you may want to use one of the following sites.
You can upload an image just like the one you used in your question and they will return you the font name most of the time.