bill - 12:12 am on Oct 21, 2007 (gmt 0)

That's not as easy to do as you might expect. Setting a default browser from an Admin account sets the preferences for all profiles. Here are a couple of options:

1. Use virtual machines
   If one or both of you work in a VM all of your programs and associations can work independently. Gaming performance might suffer, but regular operations should be about the same.
   
2. Use software
   This donation-ware is from a MS MVP and I've seen recommended a lot:
   [windowsxp.mvps.org ]