system
35
Found there is one registry entry under:
HKLM\SOFTWARE\Mozilla\Firefox\extensions
This entry points to a folder with a long apparently random name beginning “{CB0FF5E6-0E” located in:
C:\Documents and Settings\Administrator\Local Settings\Application Data
Restarted Firefox after removing the folder then found XULRunner no longer listed on the extensions page.
The offending folder contains 2 sub-folder and 4 files including a javascript program which presumably does the URL mangling.
Now need to find what put it there.
Thanks for your comments about old versions. I don’t know where it’s finding Firefox 3.0.11 I have been using FF4 and have now upgraded to FF5. Yes I do need to upgrade Thunderbird2 to TB5.