You can do it through Windows pretty easily. If you right click on one of those .abc files, in Win2k there should be an option near the top called Open With. This will bring up a list of all the programs installed in your system. If your program is not on that list then use the Other key at the bottom and select it that way. Once you pick the .exe file you want, Windows will associate your program with those .abc files.
Undeadlord