Disk Boot Failure

I am using XP home sp2, AMD dual core and Samsung SATA 120GB hard drive.
After recently formatting the hard drive and installing XP home and updates,
it won't boot up normally. I have to have the XP disk in otherwise I get the
disk boot failure. Tried pressing F8 at start up, but that didn't work.
Everything works fine as long as the XP disk is in the drive. Any Ideas.
Thank you in advance.
Rod