Better still than Better still, do both!
If you've never tweaked VISTA it's probably like XP, instead of file names with extensions you're looking at pictures.
http://www.trainsim.com/vbts/showthr...er-for-dummies
Set it up so file extensions aren't hidden, then you won't be trying to open a DAT file when you think it's a UPC or CGF file.
Also when you right click on a file and select "Open With" then "Choose Program" there's a check box in the lower left corner, "Always use the selected program to open this kind of file". Check that ON and you can just double click on any file with a UPC or CFG extension and it will automagically open in notepad.