Try Printscreen or shift+printscreen. The method said by walkie techie is good one. if u r not successfull with printscreen or shift+printscreen. Try walking techies method i.e; hit alt+enter, maximize to maximum size possible but u shud be able to see taskbar if autohide taskbar is disabled. Goto paintbrush, and cut only that part of screen that u wud have seen in full mode.
I use ne of these methods.