How do I run any program is DOS without using the location?

Hey, even a master needs some help. I'm making a "present" for a friend of mine (don't worry, nothing bad, just outright annoying!). I need to run Internet Explorer or Firefox from DOS. Is there anyway of doing this without specifying the location of the executable? I would like to use Firefox, but I Explorer would be great. I want him to click on it and bring up a website. Thanks in advance.