Is it possible for a 1998 windows xp computer to run fornite?

No. Windows XP didn't come out until 2001. Fortnite's system requirements are much higher than any computer available in 1998 (or 2001).

Yup, keep trying fool.

Anything is possible with enough mods.  You'd have to mod your video driver, chipset and game to function on XP.  Could be done.  But will it be done, very unlikely because of security issues.