|While restoring the registry may get you going again it would probably be best if you reinstalled IE over the top of itself to both renew the proper registry entries and to refresh your IE files as the Customize function is a dll "feature".|
I'm thinking mainly of the wallpaper addition to IE in the old IE 5.00 tbwlpapr.exe update. The update was mostly bmp files. It had one .hta and one .inf file that worked the hook that was already in place inside the shell32.dll file. It's little known that Windows Explorer can have the same Wallpaper as IE. For example:
Despite all warnings to the contrary, this IE 5.00 "only" update still works fine with IE 6.
To reinstall IE correctly, double click on the ie6setup.exe file and select Custom, to then manually check each box of all the items that were installed before. Only when this is done will the files be extracted from the IE cab files and used to overwrite your current files. It takes all of five minutes if you have the files on hand, the only drawback is that you will have an IE icon placed on the desktop again if you happened to remove it before.
In particular you will want to get update 313829, also known as "Security Update, March 7, 2002, Unchecked Buffer in Windows Shell" (Windows Update Catalog) that has the updated shell32.dll within it. You will also have to re-apply some WinUp updates according to the scan at the site.
Re-application of updates is just like the reinstallation of IE in that same versioned files will get overwritten with fresh files and thus renewed.