I can understand your Mom's point of view. The Older Generation is very afraid of these "new fangled computer things" and wants as trouble-free an experience as possible. My Mom is 70 years old. The microwave is still intimidating to her. I've tried for years to get her to use WebTV (I'd pay for it) so I could email pics of me, my son, my life, etc...but she just refuses to learn. Oh well.
Oh yeah, back to your query.

Tell her to get a Dell. A nice PIII system. I believe they are still selling the 933 Dimension series. It's quiet, it'll never need a 4-in-1 driver...It should run for years with absolutely no maintenance.
Everyone on this forum is a custom-build junkie, but for some folks (Moms especially) it's much, much better to go w/a realiable prebuilt box. Good luck to you and you Mom.