It's likely their install will detect and refuse to run under Windows 98, since that's very easy to do.
There's really no need to debate Windows XP vs 98. Face reality. You aren't going to change their minds. I'll tell you one thing, you certainly aren't going to be building Windows apps under 98. I haven't touched 98 since the days of NT 4.0 for development.
I've been using XP for the last 2 years and maybe blue screened twice.
This comment was edited on Jul 27, 22:33.