The title says it all, really. A list of some lesser-known keyboard shortcuts that you can use to be more productive in Windows.
Win+E: Opens Windows Explorer
Win+M: Minimises all windows
Ctrl+Shift+Esc: Opens Task Manager (or the much better Sysintern als Process Explorer, if you have it installed)
Alt+D: Moves to the address bar and select the current URL
Ctrl+Enter: Automatically adds a leading www. and trailing .com to what you have typed in the address bar, then navigate to it. So, for example, typing swref then pressing Ctrl+Enter will take you to http://www.swref.com.
F11: Toggles full-screen mode
Backspace: Goes back to the previous page
Ctrl+Alt+1: Applies the Heading 1 style to the current paragraph (the equivalent shortcut keys work for Heading 2 and Heading 3 as well)
Shift+F5: Jumps between recent edit points
Ctrl+Q and Ctrl+Space: Removes paragraph and character formatting respectively
Ctrl+’: Copies content from the cell(s) immediately above