Help with Reformatting!?

I have a windows 98 that I just bought. It is a computer I plan on using to Just play with. I have tried many things and failed miserably on the OS. I am trying to install windows XP. I have a disk and the key and everything! When I boot it up, I have tried to boot from CD but it never does. Then when It is up and I go to computer and the cd drive, it says there was no CD found in drive. I then tried through command prompt or in this case MS-DOS. Still doesn't find anything in the CD drive. I have no idea what to do! Can anyone help me and please any information is needed.