In the following, capital letters are just used for clarity.

If you haven't learned the four basic keyboard commands yet, do so.  Used in conjunction with the shift key to highlight objects or text, they'll make your computing life much easier, promise.

They are:

• Ctrl-A highlights the entire page or window
   
• Ctrl-C copies highlighted entry to memory, called the "Clipboard" by Windows
   
• Ctrl-X deletes the highlighted entry, copies to Clipboard
   
• Ctrl-V pastes the Clipboard onto page

Note that you always press the Control key down first, before any other accompanying keys.

So just remember it's:

• A for All
• C for Copy
• X for X-out

The only one that doesn't fit in is "V for Paste", since Ctrl-P is used for "Print".  The V is the only one you have to remember, and it's right next to the X and C, so there shouldn't be any problem.

You should also learn the most common keyboard commands for programs you use.  Most programs use the above, as well as:

• Ctrl-L — Left-justifies text or picture
   
• Ctrl-E — Center-justifies
   
• Ctrl-R — Right-justifies
   
• Ctrl-F — Opens the Find box
   
• Ctrl-Z — The biggest lifesaver of them all — the Undo command
   
• Ctrl-Y — And if things really get crazy, the Undo-Undo command!

Sometimes a program will have a small variation, like using Ctrl-Shift-C for 'Center Justified'.  The menus in the program should note if there's a keyboard shortcut.

A full list of keyboard commands is here.