Unless you upgraded the 98 install (in which case if you chose the option to save your present setup enabling you to go back) then you will be best to reformat and reinstall 98.
What problems are you having with XP there are many here who can help?
OnePlus 5T review: Hands-on
See the Best Button Badge Designs of 2017
iPhone X review
Black Friday 2017 : date, sites participants & bonnes affaires