The NTLDR and/or NTDETECT.COM files may be corrupted. Use the following steps to replace these files. 
Corrupt NTLDR and/or NTDETECT.COM file
The NTLDR and/or NTDETECT.COM files may be corrupted. Use the following steps to replace these files. This method is for Windows XP users.
1. Insert the Windows XP bootable CD into the optical (CD or DVD) drive and restart the notebook.
2. When prompted to press any key to boot from the CD, press any key on the keyboard.
3. Once in the Welcome to Setup screen, press the R key to repair Windows.
4. Press the 1 key and then press Enter.
5. Type the Administrator password at the prompt.
6. Copy the NTLDR and NTDETECT.COM files to the root directory using the following steps:
1. Type copy d:i386ntldr c: (assumes the optical (CD or DVD) drive is d) and then press the Enter key.
2. Press the Y key at the Overwrite ntldr? prompt.
3. Type copy d:i386ntdetect.com c: and then press the Enter key.
4. Press the Y key at the Overwrite ntldr? prompt.
Once both files have been successfully copied, remove the CD from the optical (CD or DVD) drive and type exit at the prompt and then press the Enter key. The notebook will reboot.
