Log in as administrator, open Windows Explorer, navigate to Documents and Settings → All Users → Desktop and drag the M2M Studio icon there. This will make the icon appear on all users desktops. Not ideal, but a workaround.
If you edit
\configuration\.settings\org.eclipse.ui.ide.prefs
(under your M2M Studio installation folder), you can change the list of recent workspaces to point to wherever you want. You can also re-show the workspace selection dialog at start-up if you have checked the Use this as default and do not ask again check box at startup.
This is probably a fault in the Eclipse installer than a strictly M2M studio issue.
BTW, you shouldn’t need to be administrator to install M2M Studio. Eclipse (basis of M2M studio) can be installed by anybody - into any directory that the user has write/modify access to. The Eclipse install has been specifically designed so that is doesn’t require write access to either the registry or other system directories. You can (and I do) have multiple copies (different versions) installed side by side without interference - as long as you don’t install them in the same directory!.
Of course, somebody is about to prove me wrong…
You shouldn’t have to do this though - these little niggles should be reported to the upstream devs…