bat-files suddenly associated w. MS WORD - how to get back to normal?

I use a few .bat files to do simple chores, such as copying newly changed files to a backup folder.
Suddenly these bat-files associate with MS WORD and open there instead of doing their batch work.
I suspect that maybe some recent Vista updates (they come in droves) are responsible for this mess.
How do I get back to normal?

Vennlig hilsen / Best regards,
Christian F. Scheel sr.
Oslo, Norway