Repair unbootable disk?

I have two Dell D800s that I try to keep nearly identical and up to date in order to have a hot spare if one crashes. The other night I turned on the spare to allow it to update itself, but it wouldn't boot. After the BIOS, all I get is a black screen with a flashing cursor in the upper left-hand corner.

Very odd, since the last shutdown was completely normal, and it wasn't exposed to any malware the last time it was on.

I booted from a CD and ran chkdsk /r. After it finished I ran /p, and it declared the disk to be error free. I ran Dell Diagnostics, and it declared the hardware to be fine. Inserting an old 30 gig drive that still works also confirmed that there was no hardware problem in the computer.

Someone I talked to said there was a way I could create a repair CD on my working computer and run it on the bad one to try to ferret out what appears to be a corrupted registry or boot file. I can't find out how to do this. Does anyone know how?
burn a cd of Hiren's boot cd, instructions below, or since you can boot into the recovery console, you can run fixboot and fixmbr, instructions for that also will follow,

Courtesy of Jose Ibarra
Make yourself a Hiren's Boot CD which you can download from here:

The ZIP file is large, so the download will probably take a little while to complete bit it is worth it. Then unzip the download to extract the Hirens.BootCD.ISO file that will be used to create your new bootable CD.

Creating a bootable CD from a .ISO file is not the same as just copying the .ISO file to a blank CD. You have to use software that understands how to burn a .ISO file to a CD to create a bootable CD.

In the Hiren's ZIP file are the BurnToCD.cmd file that you can double click to launch it, but I have never used it and prefer to use ImgBurn.

If you need a free and easy CD burning software package, here is a popular free program:

When installing ImgBurn, DO NOT install anything from UniBlue or the Ask toolbar (never install the ASK toolbar for anything).

Here are some instructions for ImgBurn:

It would be a good idea to test your new bootable CD on a computer that is working.

You may need to adjust the computer BIOS settings to use the CD ROM drive as the first boot device instead of the hard disk.

These adjustments are made before Windows tries to load. If you miss it, you will have to reboot the system again.

When booting on the Hiren's CD you will see a menu of options. Choose the Mini XP option. Then it will appear that Windows is being loaded and you will be presented with a desktop that has the look and feel of the Windows Explorer interface you are already used to using.

One way to check the disk for errors is to open My Computer and right click your afflicted drive and choose Properties, Tools, Error-checking, Check Now... put a check mark in both the boxes and then Start.

Sometimes that doesn't work, so you can also click Start, Run and in the box enter:


Click OK to open a Command Prompt window and enter the following command (assuming XP is installed on your C drive)

chkdsk c: /r

This disk checking can take a long time (perhaps several to many hours) depending on the size of the volume, the amount of data on the volume and what the disk checking finds to do.
Let chkdsk finish and correct any problems it might find.

Depending on the the speed of your system, the size of the volume, the amount of data on the volume and what chkdsk finds to do, it may take a long time for chkdsk with error correction to complete (several to many hours) or it may appear to be 'stuck'. Be patient. If the HDD light is still flashing, chkdsk is doing something so don't interrupt it. It will finish eventually one way or the other. Keep an eye on the percentage amount to be sure it is still making progress. It may even appear to go backwards sometimes.

You may have to run the chkdsk c: /r more than once.

What you want is fixboot and/or fixmbr:

The fixboot command writes a new partition boot sector to the system partition that you specify.
fixboot (drive)
drive = This is the drive that a boot sector will be written to and will replace the system partition that you're currently logged on to. If no drive is specified, the boot sector will be written to the system partition that you're currently logged on to.
Fixboot Command Examples:
fixboot c:
In the above example, the boot sector is written to the partition that's currently labeled as the C: drive - most likely the partition you are currently logged on to. If that is the case, this command could be run without the c: option.
Fixboot Command Availability:
The fixboot command is only available from within the Recovery Console in Windows 2000 and Windows XP.

The fixmbr command writes a new master boot record to the hard disk drive that you specify.
Fixmbr Command Syntax:
fixmbr (device_name)
device_name = This is where you designate the exact drive location that a master boot record will be written to. If no device is specified, the master boot record will be written to the primary boot drive.
Fixmbr Command Examples:
fixmbr \Device\HardDisk0
In the above example, the master boot record is written to the drive located at \Device\HardDisk0.
In this example, the master boot record is written to the device that your primary system is loaded onto. If you have a single installation of Windows installed, which is normally the case, running the fixmbr command in this way is usually the right way to go.