Grandma's new computer

My mum has gotten my grandma a computer and an internet. I'm visiting for the weekend, and I've been informed that I'm going to set up antivirus, firewall, email etc. I assume it's running XP, although I haven't had a look yet.

Shall I take this opportunity to install SuSE? I don't think she's had time to get particularly attached to her current OS. She uses winders at work, but does nothing but use Sage, Minesweeper and occasionally notepad.

OK, having asked your advice I'm gonna ignore it because you're not telling me what I want to hear. She'll be running Suse before the weekend is out.