Do you actually get "NTLDR is Missing" error? I am assuming you have XP as your operating system?
If so try this.
Load Windows XP CD into CD drive.
Make sure BIOS is set to boot to CD drive.
Boot the computer from CD.
At menu, press "R" to load Recovery Console.
Select the installation to be fixed.
*The following instructions assume CD-ROM is labeled as drive D and the hard drive partition the windows installation is on is labeled as drive C. Replace the letters accordingly.
Type "COPY D:\i386\ntldr C:\" and press ENTER.
Type "COPY D:\i386\ntdetect.com C:\" and press ENTER.
Remove CD and type "EXIT" and press ENTER (to reboot your computer)