Its a component of the IE6 setup program, you will not find it on your
harddrive.
You access it by entering in the following in your Run dialog (Start\Run
menu)
rundll32 setupwbv.dll,IE6Maintenance
a requirement is that you have already installed IE6 on your computer and
that setupwbv.dll is in your windows system folder
I have used it on a number of occasions to fix common problems with IE.
Choose the repair option in most instances (this will check the versions of
the support files for IE and update or download them for you if necessary)