Question : Help!  Why are my desktop icons changing to "no program" icon?

The icons on my desktop are changing to "no" program icon.  
A week ago, this affected the Active Directory shortcut.
Today, it has affected Adobe, Dell Server Administrator, Symantec AntiVirus and WordPerfect shortcuts.
Note:  All shortcuts still work.
What is going on here?

Answer : Help!  Why are my desktop icons changing to "no program" icon?

Looks like you have "cleaned up" the installer folder. Try the following:

Open the link in an editor, e.g. by opening the explorer in your Start Menu folder,  and open one of those links with notepad. You will see the path used for the icon at the end (twice), it will look like
%SystemRoot%\Installer\{AC76BA86-7AD7-1031-7B44-A91000000001}\SC_Reader.ico

(that's Adobe Acrobat Reader 9). Observe that folders for existence. %SystenRoot% is C:\Windows in most cases.