The icon which shows up in the taskbar is set in the application itself. As to how to get Start | Programs back to the original icon, go into properties and choose to change the icon again. Point it back at the Query Analyzer executable (isqlw.exe) as the file to look at for icons. Default path is:
C:\Program Files\Microsoft SQL Server\80\Tools\Binn\isqlw.exe
You should then see the original icon as a choice you can select.
K. Brian Kelley
@kbriankelley