How To Make FireFox Main Browser?

I've just recently loaded FireFox on my computer as was suggested by many on this site and whenever possible forget about using IE.

This may be a simple answer for most but here it goes... when I'm working on a program like Photoshop and click on the help file it opens Internet Explorer to go to that site. How can I default it so it will open in FireFox instead? I have Microsoft XP on my computer.

Thanks for the help in advance

 

There should be a pop-up asking you if you want to make FireFox the default browser every time that you open it, if you haven't done so already.

 

Tools-Options-General-Check firefox default browser