Make sure that there isn't a floppy disk in your drive. If there isn't, then check out this site.
NTLDR is Missing:
http://www.computerhope.com/issues/ch000465.htm
If there's nothing useful there, try this:
Boot up with the XP CD in the drive and go to the Recovery Console. At the command prompt type "bootcfg /rebuild" without the quotes.
Description of the Windows XP Recovery Console
http://support.microsoft.com/default...b;en-us;314058