Cause: This problem may occur if the Ntfs.sys file is missing or becomes corrupted when you convert your hard disk to NTFS.
To resolve this problem, you must replace the missing or corrupted Ntfs.sys file. To do so, follow these steps:
1.Start your computer with the Windows XP CD-ROM in the CD-ROM drive.
2.You are prompted with the following option:
To repair a Windows XP installation using Recovery Console, press R
When you are prompted with this option, press R to select it.
3.At the command prompt, type the following commands (press ENTER after each command):
cd \windows\system32\drivers
ren ntfs.sys ntfs.old
**Note This step renames the corrupted Ntfs.sys file to Ntfs.old. If the Ntfs.sys file is not found, then the file was missing.**
4.At the command prompt, type the following command, and then press ENTER:
copy cd:\i386\ntfs.sys drive:\windows\system32\drivers
Where cd is the drive letter for the CD-ROM drive that contains the Windows XP CD, and drive is the drive that you
installed Windows XP to.
5.Remove the Windows XP CD from your CD-ROM drive, type quit, and then press ENTER to quit the Recovery
Console.
6.Restart Windows XP