Just acquired a Microsoft Surface Pro and I was wondering how to take a screenshot when the keyboard is not connected. After a few seconds using my favorite search engine I came across the key combo to do it and was amazed.
To take a screenshot on a Surface device PRO or RT, press the Windows button and volume down, yes that is right! Windows+Volume Down. It must be the Volume Down on the device not the one on the keyboard.
The screenshots will be stored on the Screenshots folder inside the Pictures folder.