1. Click onto Start > run > regedit and Press OK.
2. HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Internet Explorer > Setup > 7.0
3. If the key DoNotAllowIE70 is present and the Dword value is 0, IE7 will be offered as optional downloads only, and not as a high priority update which will required your action. To prevent and block the download and install of IE7, simply modify the value of DoNotAllowIE70 to 1.
4. If the key is not present, create a new DWORD key DoNotAllowIE70 with value as 1. However, the user can still manually download and install IE7.