PLease try these steps::---
To resolve this behavior, replace the Windows XP Ntldr and Ntdetect.com
files. Follow these steps:
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Start the Recovery Console, type fixboot at the prompt, and then press ENTER.
If the Recovery Console does not appear, follow these steps:
Use one of the following methods to start the computer so that you can
access the file system of the boot partition:
Specify another operating system on the Boot menu.
Start from the Windows XP CD-ROM, and then at the Windows Setup screen,
press "R" to use the Recovery Console to repair the Windows installation.
Use a Windows NT 4.0 boot disk that also contains the Windows XP boot files.
If your boot partition is a basic disk that is formatted with the FAT file
system, use an MS-DOS boot disk.
Copy the Ntldr and Ntdetect.com files from the I386 folder on the Windows XP
CD-ROM to the root folder of your boot drive. The boot drive is typically
drive C.
If you are using MS-DOS to perform this file replacement, you may have to
remove the System attribute, the Read-only attribute, and the Hidden
attribute from the files by using the attrib command. To do this, type the
following lines at the MS-DOS command prompt, and then press ENTER after each
line:
attrib ntdetect.com -r -s -h
attrib ntldr -r -s -h