I have a situation in which my Windows XP doesn't boot if there is not a Windows XP CD inserted. I am facing this problem for the first time. Do you know how to fix this?
This is a bit of a guess.
Without a more detailed description of what exactly happens when you turn the computer on I can't be more specific.
I presume that in your case the CD starts to boot.
You get the message 'Press any key to continue boot from CD' and you DON'T press anything.
After the timeout (some 10 seconds) the normal boot from harddisk begins.
Seems you changed the order in which the BIOS tries from which device the computer can boot.
In some computers if the CD has priority over the harddisk it really needs a bootable CD to be present.
It can also be that you removed the harddisk from the list of bootable devices alltogether. (This won't prevent the CD to hand-over control to the harddisk, just prevents the harddisk from booting without help.)
I would check the Bios settings related to boot-devices. Something appears to be iffy there.