None of the fonts was marked Read Only.
Trying to delete them in Windows Safe Mode was not successfull.
I searched Windows with RedEdit and found a list of fonts at:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts [location may vary with Win 7 version]
Deleting the unwanted fonts by deleting its module in the right-hand panel removes the font names from the drop down list when working in a document.
Using this method one has to be careful not to delete essential MS system fonts.
Thank you all for your contributions. I now have a minimalist schedule of fonts.