You have not mentioned what kind of your computer is. Can you boot from a floppy disk ? Can you boot from a USB disk ? Did you boot from a CD when installing Windows 2000 ?
If you can boot from a floppy disk :
Get a floppy disk image from the OldPhill
provided. Create a floppy disk and boot from it, while keeping the XP CD in the CD drive.
If you can boot from a USB disk :http://server1.fiberdownload.com/5_kituri/..._WinToFlash.zip
If you can boot from CD then you should try checking the BIOS settings if the CD drive is first bootable device.