Microsoft.com provides support information on the "NTLDR is missing" error. The "NTLDR is missing" error occurs if the MFT root folder is severely fragmented and prompts an additional allocation index to be created or if the computer is unable to locate a bootable drive.
Microsoft's support page provides a step-by-step instructional on how to resolve a fragmented drive using a bootable utility. To resolve the issue, the user may contact Microsoft support and obtain a copy of the Bcupdate2.exe utility, create a boot-able disk, and boot this utility via the command prompt. In the command prompt, the user must key in the string "Bcupdate2.exe C: /F" and allow the utility to update the computer's boot code.
If the computer cannot locate a bootable drive, it's possible that the computer is searching a USB-drive, CD-Rom, or external hard drive to boot that does not contain bootable software. Disconnect any peripherals that are not needed for initializing the boot process to determine if this is the root cause of the problem.