Ok, I don't believe I did this, but I did.
I have office 2003 installed on my computer. I wanted a shortcut to Word on my desktop, so I went to Start > All Programs > Office and then dragged the Word icon to the desktop. It created a shortcut ok, but it also removed the listing from the list of programs that are installed on the computer under All Programs!
I think what I should have done is to right click on the Word icon, and choose Create a Shortcut. Then drag the shortcut onto the desktop.
BUT WAIT, there's more!
I didn't worry too much about the missing listing as I was going to install Office 2007 anyway. So, guess what.... after installing 2007 I wanted a shortcut to Word on the desktop, so I dragged... well I think you can fill in the rest... yes, that's right, I did it again! So now there is no listing for Word under Office 2007 in All Programs list either.
How can I reverse this so that I can have both the listing and the shortcut?