blocking IE 7 from auto-installing through the registry
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Setup\7.0]
"DoNotAllowIE70"=dword:00000001
This registry key will block IE 7 from autoinstalling, but will not block a user from manually installing it. You can simply save this text in a file called "noie7.reg" using notepad and then double click it to add the key to your registry.
For more check out Miscorsoft's website here: http://www.microsoft.com/downloads/details.aspx?FamilyId=4516A6F7-5D44-482B-9DBD-869B4A90159C&displaylang=en
Steve G.