Windows Keyboard Shortcuts:
CTRL + C: Copy
CTRL + X: Cut
CTRL + V: Paste
CTRL + Z: Undo
CTRL + B: Bold
CTRL + U: Underline
CTRL + I: Italic
CTRL + A: Select all
ALT + F4: Quit a program/Shut down
ALT + TAB: Switch between open programs

SHIFT + TAB: Tab backwards through a form
ALT + underlined letter in menu: Opens the menu
CTRL + ESC: Open Start menu
F1: Open Windows Help menu
F2: Rename a file
F3: Find all files
SHIFT + RESTART: To restart Windows and not your whole computer, hold down the SHIFT key when you click the OK button on the Shut Down screen. This will save a lot of time.
Windows key + D: Show the Desktop
Windows key + M: Minimize all windows
Windows key + SHIFT + M: Undo minimize all windows
CTRL while dragging a file: Copy the file
CTRL + SHIFT while dragging a file: Create a shortcut to the file
And there are more options if you have special needs: you can adjust the Accessibility Options of your keyboard and mouse in the Control Panel. You can allow Sticky Keys (one key at a time for key combinations), Toggle Keys, and allow extra keyboard shortcuts in programs.
 
Internet Explorer 6 for Windows Keyboard Shortcuts
If you use Internet Explorer as your Web browser, there are some shortcuts that can help you get to where you’re going on the Web faster.
CTRL + ENTER: Adds "www. to the beginning and ".com to the end of the text typed in the Address bar.
CTRL + D: Adds the current page to your Favorites.
F4: Displays a list of Web addresses (URLs) you’ve typed
CTRL + F: Find on this page.
ALT + HOME: Go to your Home Page
CTRL + N: Open a new window
CTRL + I: Open the Favorites bar
CTRL + H: Open the History bar
F5 or CTRL + R: Refresh the current Web page
CTRL + S: Save the current page
ALT + D: Select the text in the Address bar
ESC: Stop downloading the page
ALT + Plus: Zoom in
ALT + Minus: Zoom out
ALT + Back Arrow: Go back
ALT + Forward Arrow: Go forward
Just think about all the time you'll save!