Why do Icons keep poping up on my desktop?

[mod9k]

I open any program like AutoCAD or Adobe and even if I already have an shortcut icon on the desktop for that program, Windows 7 always places another shortcut icon for the same program on the desktop.

Does anyone know why it does this and how to stop it?

 

[mod9k]

I also noticed that it keeps adding explorer to the task bar. I've added "Quick Launch" which is where I have the explorer icon but Windows 7 keeps "pinning" it to the task bar as well.