If I upgrade my old 98SE Comp to XP Pro will I lose my existing files? Will I have to reinstall drivers? How is that done, if necessary?
Thank you for your help.

No, you won't lose them. I just did 98 to XP upgrade, and all old data was transferred to XP. Just remeber to save/backup your data once you upgrade to XP, because if you have to reinstall it, data won't be saved.