One of the most important techniques to master on computers is the click and drag technique.
This is used to move files or copy them to different folders or disk drives, to size boxes and shapes, for instance when creating a box to hold text in a document or when sizing a photograph imported into a page of text.
It is also used extensively in spreadsheets to create a range of numbers or to apply a format or style to a number of cells in the spreadsheet.
It can also be used on the Desktop to arrange the icons how you want them.
That's what I've done in the picture - I've used click and drag to move the Picasa icon to the right. This shows both before and after for illustration. Moving an icon in this way on the Desktop would not create a copy.
How to click and drag? First point the mouse (move the mouse until the pointer is over the icon or file to be moved, then press and hold down the left button and without releasing the button move the mouse until the pointer is where you want the icon or file to be. Now release the mouse button and the movement will be completed.