|You need to understand the odds of you being successful with a multiboot [installing 98 after xp will result in you not booting xp] is slim to none.|
It isn't just a matter of OS but of advancing hardware. We had to quit installing 98 because new hardware had no drivers for 98. Especially new printers, no 98 support.
Smart folks cycle out their hardware so they are not caught with antiquated hardware. I have boxes in the basement full of the stuff [shows how smart I am].
If you decide to try consider loading VM [virtual machine - ms virtual pc or vmware] which runs on xp and allows you to "host" an older OS.
A one sentence question will result in a one sentence answer.