in the firefox options<general there is a thing that says set default browser see if that works. I like mozilla better anyways your mom is probably not into computers.

Start up IE and it should ask if you want to make it the default browser.

She is, actually she's in charge of our network, but she's never tried Firefox before and wants to make sure she likes it before she sets it as the default. As fanatical of Firefox as I am, I don't see how this is unreasonable.

I tried and IE is not asking to be the default browser. I checked Internet Options and it IS set to check, so something's wrong here.

Open IE.

Click on Tools, then Internet Options. Click on the Programs tab. There should be a button there that says "Reset Web Settings...". Click on that-- it will reset all of your Internet Programs to their default settings.

I apoligize. The problem seems to have gone away now. For some reason IE suddenly started asking to be the default again. By this time, however, my Mom had decided she liked Firefox better and didn't need IE anymore.