File extension in XP

I have been using an ancient program called Card Studio that was made years ago. It is a Hallmark program. I have installed it on my XP laptop, transferred all my old data to the laptop with no problems... (*.csf files.)

On my new desktop running XP, when I tried to transfer the data files, it tells me the file extension is not a valid one (.csf) and it is searching for a .csv file.

Where/what is happening that it isn't accepting the .csf file extension?
Thanks a bunch.

 

HOW TO: Change File Associations in Windows XP includes a section on setting up a new association.

 

Thanks Newt. I'll never know why one new install of XP Sp1 needed tweaking on that file, and the other new install of XP Sp1 didn't. Oh well, so long as it works! ha Thank you so much.