I had the same problem with updating from IE5 to IE6. Can't remember
where I
saw this, but it works.
Go to: My computer / tools / folder options / view
         Select "show hidden files and folders"
         Click "OK"
Go back to desktop. Right click on desktop/ click "new" to create a new
folder on your desktop. Name it  "Old Uninstall" (without the brackets).
Go to: My computer / C / Program Files / Internet Explorer / Uninstall
Information
Click:  Edit / Select all / Cut
Go back to your desktop and open the "Old Uninstall" folder you created.
Right click inside it,  and click "Paste".
Go to set up for IE6 and install normally.
Should install everything now. If everything works, delete the "Old
Uninstall" folder on your desktop.
Hope this helps.