Matthew -
You may also wish to incorporate a method, for future changes, to check/overwrite shortcuts in other locations that the user may move the desktop icon to, including Start Menu and Quick Launch bar. Otherwise, users may end up with multiple versions of a shortcut. These locations can include, depending upon O/S:

WinXP/2K
%SystemDrive%\Documents and Settings\@USERID\Application Data\Microsoft\Internet Explorer\Quick Launch
%SystemDrive%\Documents and Settings\@USERID\Start Menu\Programs
%SystemDrive%\Documents and Settings\@USERID\Start Menu
%SystemDrive%\Documents and Settings\@USERID\Desktop
%SystemDrive%\Documents and Settings\All Users\Start Menu\Programs
%SystemDrive%\Documents and Settings\All Users\Start Menu
%SystemDrive%\Documents and Settings\All Users\Desktop

WinNT
%windir%\Profiles\@USERID\Application Data\Microsoft\Internet Explorer\Quick Launch
%windir%\Profiles\@USERID\Start Menu\Programs
%windir%\Profiles\@USERID\Start Menu
%windir%\Profiles\@USERID\Desktop
%windir%\Profiles\All Users\Start Menu\Programs
%windir%\Profiles\All Users\Start Menu
%windir%\Profiles\All Users\Desktop

Win9x
%windir%\Start Menu\Programs
%windir%\Start Menu
%windir%\DeskTop

Bill