How does one put an icon for launching an application onto the desktop? 

Do you want to copy a shortcut icon from the desktop to the QuickLaunch bar or vice versa? Ctrl-drag the icon from place to place, or right-drag, selecting "copy". 

You can also ctrl-drag or right-drag an icon from the exploding Start menu onto the Desktop. Again, choose copy to leave the item on the Start menu. 

If there is NO icon anywhere that starts a program, you can search out the actual program file (like Excel.exe), and right-drag it to the desktop, choosing the "create a shortcut" option. 

But you don't want to remove the quicklaunch icon, you just want a copy of it someplace else.  So hold down the Ctrl- key on the keyboard while dragging with the mouse. The "+" attached to the mousepointer indicates that a copy is in progress. 

Shift-mouse-drag always moves. Ctrl-mouse-drag always copies ("C is for copy"). 

You can avoid memorizing this drag and drop rule, and simplify everything, by always using the right (alternate) mouse button to drag and drop. 

But the right button -- the left button if you have set up your mouse for left handed use --  the alternate-button -- "right-click" by convention -- has a purpose.  

You can use right-click to view the pop-up "context menu" for an object, and thence perhaps to examine its properties.  Try it.  Aim at something on your computer screen right now and right-click.  Try it!

• Maybe you were offered a menu of things you could do with this Web page (if you pointed to some open space on this Web page).  Depending on the capabilities of your browser, that menu might have included "View Source", "Back", "Add to Favorites" or even "Links List".   
• If you pointed to a link or hotspot on my page, other options might appear, such as "Open Link in New Window."  That can be a useful one sometimes.  
• If you pointed to a graphic, the popular option "save picture as..." might be available.  See how useful this is?
• Maybe the program offered to let you customize a toolbar (if you pointed to a toolbar).
• Maybe you got an offer to cut, copy or paste the current URL (if you pointed to the "Address:" bar.
• Maybe the program offered to let you customize the Start menu or Quick Launch bar (if you pointed to those screen elements).
• Finally (for our purposes) if you pointed to the open space around the Internet Explorer window -- assuming no other programs were running and IE was not running full-screen -- the area known as the desktop -- you might be offered the chance to change the properties of your display itself -- the screen resolution on your monitor, the screen saver, the overall Windows color scheme, and much more.

Only the plausible options will appear on the menu.  Plausible but currently impossible options may appear greyed out.

The bold item on the pop-up menu is the "default" action for this object. That is the action that would occur if you double-clicked on the object with the mouse, or selected the object and pressed Enter. 

If you don't see anything on the menu you like, choose cancel (or click outside the pop-up menu, or press the "Esc" key) and do something else instead.

Oh yeah, by the way... once you have popped open the menu, you select from it with the regular, left button.  

People always ask that.

But what does this have to do with drag and drop?

Right-mouse-button-held-down-dragging an object begins an operation, but when you drop you get a pop-up menu, from which you can choose to move, to copy, to create a shortcut, or to cancel the whole operation. 

The bold item on the pop-up menu is the "default" mouse action. That is the one that would happen if you just plain-dragged with the mouse. 

Knowing how to copy and move files around -- on to and off of various kinds of disks -- is half the battle. 

The other half is knowing 
when to copy them,
when to move them,
and when to leave them alone. 

A block of text can be an object, but you have to select the text first.  A graphic element in a drawing, a range of cells in a spreadsheet, a message in your e-mail program, all of these are objects that can be usefully manipulated using drag and drop.

An icon can be an object.  Sometimes an icon acts symbolically, and the drag operation affects not so much the icon as the file or device that that icon represents. Drag a file icon to a printer icon and the document prints (in theory).  

Pre-selecting several files before beginning a drag-and-drop action will let you move or copy all the files at once.  

(Using the mouse or keyboard to select multiple objects is a separate art... use your intuition and experiment using the ctrl- and shift keys.) 

Icons may also represent programs.  Usually, these are really just "shortcut" icons that point to the location of the primary program file.  But copying these icons to places like the Quick launch toolbar or the Start menu or the desktop or even your "Send To" folder can help make it more convenient to start up these programs in various ways.

Some icons (like "My Documents" or "Outlook") are system icons, and copy will not be an option. In this case, choose "Create a shortcut" instead. 

Generally, though, don't create shortcuts that point to shortcuts. (You can recognize a shortcut by its curved-arrow corner.)

Remember: it does matter where you drop.  If you drag a file and accidentally point at a folder icon when you drop, the object will go into the folder and appear to disappear, rather than showing up beside the folder where you want it.  If you accidentally drop something in the wrong place, don't panic.  Just Edit Undo right away. 

By the way, these rules work more and more completely the more recent your Microsoft software is. 

Yep.  Wasn't that fun?  Won't knowing that help you use your online time more wisely? 

Oh, go surfing.  Class dismissed.