- Create a Microsoft Windows boot disk to start the computer. For additional information, please see the following article in the Microsoft Knowledge Base:119467 How to Create a Bootable Disk for an NTFS or FAT PartitionIf you can start the computer without errors, the damage is limited to the master boot record (MBR), boot sector, or the NTLDR file. After Windows is running, immediately back up any data of value. Use Disk Administrator to verify that partitions on the boot drive are the correct size. If there are invalid partitions, the best solution is to re-create those partitions and reformat the affected drives, then restore the data from the most recent back up tape. If the system cannot be started from a Windows boot disk, you will most likely have to reinstall Windows and restore from tape.
- Run the latest virus scanning software to verify no virus is present. MS-DOS-based virus software is sufficient for this purpose, even if the file system is NTFS. MS-DOS-based virus programs can be run from an MS-DOS boot disk.
- Ensure the master boot record (MBR) is valid. Boot from a virus-free MS-DOS version 5.0 or later boot disk with FDISK on it. Run the following command:FDISK /MBRWARNING: If your computer is infected virus, using the FDISK /MBR switch may prevent you from being able to start your computer. Before using the FDISK /MBR command, you should be certain that your computer is not infected with a virus.
Before you perform this step, see the following Microsoft Knowledge Base article:166454 Using FDISK /MBR for Troubleshooting Windows NT Boot Problems
- If the primary boot partition is a file allocation table (FAT) partition, boot from an MS-DOS disk, perform a SYS C: command to make the drive MS-DOS bootable, and then perform step 5 to replace the Windows boot sector.
- Run Windows Setup and choose the Repair option. Choose the Inspect boot Sector and Restore Startup Environment options. If the boot sector on the boot drive is corrupted, this should repair it.
- If the system still fails to boot correctly, use Attrib.exe or File Manager to remove the file attributes from the NTLDR file located in the root of the system partition. Copy a new NTLDR file from the i386 directory of the Windows CD-ROM to replace the existing one.
- If you are running Windows and the system partition is NTFS, you may have a fragmented MFT that prevents the system from booting.For additional information, click the article number about updating the boot sector below to view the article about updating the boot sector in the Microsoft Knowledge Base:228734 Windows NT Does Not Boot with Highly Fragmented MFT