F1
Activates help for current open application. If you're at the Windows Desktop, this will activate the help for Windows.
F2
Renames a highlighted icon, file, or folder in all versions of Windows.
F3
Starts find or search when at the Windows Desktop in all versions of Windows.
F4
In Windows 95 and later, this opens the drive selection or address bar when browsing files in Windows Explorer.
Pressing Alt + F4 closes the current open program window without a prompt in all versions of Windows.
Pressing Ctrl + F4 closes the open window within the current active window in Microsoft Windows. This only works in programs that support multiple windows or tabs in the same program window.
F6
While in Windows Explorer, this will move the cursor to different Windows Explorer pane or in Windows 7 browse available drives.
F8
Pressing F8 over and over as the computer is booting will start the computer in Safe Mode.
F10
Activates the File menu bar in all versions of Windows.
Simulates a right-click on selected item. This is useful if right-click is difficult or impossible using the mouse.