|You have to enter the BIOS & change the boot order. Make sure the optical drive is listed before the HDD, save the changes & exit. Then you *should* be able to boot off the XP CD.|
If the system has an SATA HDD, you'll need to load the SATA drivers at the start of the XP installation by pressing F6 & then inserting a floppy disc containing the drivers. If you don't have a floppy, you *may* be able to load them from a thumbdrive. If that doesn't work, you'll have to use a program such as nLite to create a new XP CD which contains the SATA drivers.