If you run Windows... You gotta know this!

[help_desk]

Windows Key + Tab: Cycle through the buttons in the Task Bar.
Windows Key + D: Minimize or restore all windows
Windows Key + E: Launch Windows Explorer
Windows Key + F: Launch Search for Files
Windows Key + Ctrl + F: Launch Search for Computers
Windows Key + F1: Launch the Help and Support Center
Windows Key + R: Launch the Run dialog box
Windows Key + Pause/Break: Launch System Properties dialog box
Windows Key + M: Minimizes all open windows.
Windows Key + Shift + M: Undo minimize all windows
Windows Key + L: Locks the workstation
Windows Key + U: Launch the Utility Manager
Windows Key + Ctrl + Tab: According to Microsoft: Moves focus from Start, to the Quick Launch toolbar, to the system tray. What it does for me in XP: moves through the tabs in your current application (Firefox 2, IE 7, Homesite+ and Paint Shop Pro XI)

[admin]

Good information help_desk. Thanks for this.

[Dude111]

Very usefull info