By default, the icon for the Internet Explorer 7 does not show up on the Vista desktop

To add it back in again, a registry edit is needed.
Just copy the below code and paste in notepad and save it as anyname.reg

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons\NewStartPanel]
"{871C5380-42A0-1069-A2EA-08002B30309D}"=dword:00000000

Then log off and back on again.