Sounds like originally they were opened via IE when you double clicked them.
Not sure if you get it in Win98, but right click the file, say 'Open With' then it should give you a list of programs. Find the program that used to open them before Mozilla and click the box that says something along the lines of 'Makes this the default program' (It's the only box you can check)
Click OK, and that should be it
Not sure if you get it in Win98, but right click the file, say 'Open With' then it should give you a list of programs. Find the program that used to open them before Mozilla and click the box that says something along the lines of 'Makes this the default program' (It's the only box you can check)
Click OK, and that should be it