Why can't I change the office icons on the desktop?

I have Vista Home Premium and Office 2007. I wish to change the shortcut
icons on the desktop for Word, Excel, Powerpoint, etc but the "change icon"
is not available for each shortcut. Everthing else, except one other
shortcut, can be changed easily but why not Office shortcuts? Please tell me
how to get around this.

Err why would you want to?

I've OS Windows Vista Home Premium SP1 and Office 2007 SP1.
There is no error messages, but only the Office desktops shortcuts cannot be
changed. All other desktop shortcuts I can change their icons by right
clicking the icon, opening properties, then clicking change icon. Word,
Powerpoint, Excel each have both "open file location" and "change icon"
unavailable. I've tried creating new shortcuts and replaced the icon images
but as soon as it is linked to, say Word program, the image reverts to the
standard Word icon.

If you want to "change the Icon" to the original Office shortcuts you
will need to make a Desktop shortcut to the one in the Start Menu.
(Provided you did not move them from their original location to the desktop)

I've changed icons before just so they "stood out" a bit more. I've always
used a tree for Windows Explorer instead of the default icon. I admit I
haven't changed any of the Office ones but to each his own. :-)

Thank. folks. I found a workaround to my dilenma. I placed a new generic
shortcut on the desktop then link it directly to the Office program in the
prgram files instead of going through the start menu. I can be replaced with
the original icon later as Bob I pointed out. Thanks again.

I've seen this "problem" generally happening with shortcuts created by Windows Installer. Office 2007 (as well as any earlier version since Office 2000, I believe...) uses Windows Installer to perform configuration and installation of its components. Apparently, shortcuts to Control Panel items, other system folders, and applications installed with Windows Installer cannot be changed. It would be nice to know exactly -why- this happens though...