MP3Tag missing from right clicking a file in Windows Explorer

Just installed MP3tag on a Vista machine, having previously used it on an XP machine.

I am seeing a strange behaviour with the right clicking of a file in Windows Explorer. On the XP machine MP3tag used to come up as an option but it does not know. However, if I right click on a folder the MP3tag option is there and enables me to load the whole folder of MP3's.

Any idea what has happened to the option when I right click a file?

Maybe the installation of another program wiped the entry from the context menu. Are you using foobar2000 by chance?

Yes I am, but I installed it after mp3tag and the problem was there already. I have tried re-installing and it makes no difference.