Boot device

I am trying to boot from my 160 gig hard drive where my xp operating system is located but I can not boot unless I have my other hard drive plugged in with 98 installed. I ran the xp setup from the 98 hard drive and installed it on the other hard drive. Is what I want to be able to do is have the xp hard drive be able to be independent of the 98 drive. Can anyone help?