As the previous person said, there really is no way to switch back to IE6.
While you like the system, it was necessary for Microsoft to make everyone move to IE7 for security purposes.
If you'd like to have that IE feel, Firefox can have as many (or as few) features as you'd like, and you can skin it to look like Microsoft made it. That might un-confuse your Grandma.
I haven't used Opera, but I hear that it's really good, and is the first web browser to fulfill these new standards that I can't remember (something about ACID?)...