New Internet Explorer knowledge base articles
IE7 and IE6 - Microsoft does not support changing the location of the Programs Files folder by modifying the ProgramFilesDir registry value:
When you set the ProgramFilesDir registry value to use a location other than the default location, Microsoft hotfixes, updates, and security updates do not update files that are in the default location. Therefore, you may experience system instability and unexpected problems with Microsoft programs and software updates. For example, you may experience any of the following problems:
• Microsoft hotfixes, updates, and security updates may not be installed correctly.
• New versions of Microsoft Internet Explorer or Microsoft Windows Media Player may not be installed correctly.
Additionally, the Microsoft Windows File Protection feature that helps protect files in the Internet Explorer folder does not support changing the default location of the Program Files folder.
HOTFIX - IE6 may close unexpectedly, and an access violation may occur in the mshtml.dll file when you close a popup window: