can't retain settings after power off

[Bent]

I prefer to have Firefox associated with my keyboard's "web button", as well as use the click feature of my scroll wheel on my mouse to be the "back" function to return to the previous web page. I had some work done to my computer (changed a CD-RW dirve), and now I have to go into settings and re-configure these two functions each time I do a full restart. Where would I find the selection to allow the computer to retain my preferences when I power it down?

[Kevin P]

What kind of computer, keyboard, and mouse is it?

Depending on the above, the software needed and procedure for setting button actions may be different.

In some cases, setting Firefox to be your default browser may cause it to be launched when you press the "web button".