windows 98 and I were to change to Windows XP would that get rid of a virus or would I have to change my hard drive??" - depends on how you do it.
no:
with just an update to xp you wont get rid of the virus and you have to live and deal with all the glitches that might come up.
yes:
i recommend a fresh install, that means repartitioning/formatting the harddisk, you will get rid of the virus and you have a clean xp install.
dont forget to backup your data, install and run virusscanner (check backup) before you copy data back.