Kidding, let me tell you this, To run XP, Internet Explorer, Norton anti-virus, and Zone Alarm, assuming your mom will be surfing the net a little, take 242 MBs of RAM, with only 2 IE windows open. That's completely stripped of all other programs except her modem program, also necessary. Without an email program open.
Going to crucial.com for memory is the easiest way to go, and priced competitively to boot.
Hmmm.... I'm running a PIII 700 with 192mb RAM and I can have several windows open, Zone Alarm, Norton, with a game running in another window, although no email program. I am not having any trouble doing this.
I'm also using PNY memory in my gaming computer and it's been perfect. Gosh, I feel like a rabble-rouser on this thread. :-)