Sorry to be the dissenting voice here, but Win98 will never give you the stability of XP. I've run 98 for a long time and still do in a dual boot system with XP Pro.
I'm not going to waffle too long about this because I see these kind of threads all over the place and nothing anyone says ever makes any difference.
WinXP is like every other windows operating system in one respect:
It has to be setup, updated and configured properly for it to work at it's best. If it isn't, as with any other OS, it won't perform well.
Concluding comment: How many win98 users can say they've
never had a P.C. crash/freeze/blue screen of death in 6 months of continous use?
I know a few XP users who can and I've only limited it to 6 months because that's the most I've seen reported. Personally, I've had to re-install a few times, but NOT because of the OS and 6 months is about as long as I've had it installed at any one time. I've had Win XP running FS2002 for over a year in total and I have never, repeat never, had FS2002 crash on me once - or the OS as a whole for that matter.
Nothing wrong with 98 but it simply isn't as stable (if it's set up correctly.

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