Windows could not start because the following file is missing or corrupt: WINDOWS\SYSTEM32\CONFIG\SYSTEM - fixing this without the OAM disk?

After running chkdsk /r a second time it reported NOT finding/fixing any errors. When I rebooted I got the same "Windows could not start..." message. I changed Registry back to most current but then on reboot I got a Blue screen and "system stop..." message. After F8 on boot-up I selected "Last Good Config..." Then system just kept restarting it self over and over. Then went back to next oldest Reg but got System Stop again. So I'm re running chkdsk /r... I've gotten all the data backed up so I'm just about ready to Format C: and reinstall Windows...

When troubleshooting, I would not generally make too many changes at the same time...  or else you won't know what fixed it.

The chkdsk  /r will probably fix your system up, reboot and if things look okay, boot back on Hiren's and Registry Restore Wizard to your latest RP.

It's up to you of course - probably okay no matter what you do :-)

Thanks. I guess by my not running chkdsk /r before Registry Restore Wizard was my mistake. I'm running chkdsk now and will rerun until clean. Then should I reset newest Registry before trying a reboot?

For that message, you always, always, always need to start with a chkdsk with error correction first - that will usually fix things up.  After that you may want to undo your registry restores...

Here's how:

Make yourself a Hiren's Boot CD which you can download from here:

http://www.hirensbootcd.org/download/

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:

http://www.imgburn.com/

Like many third party programs you might install, the ImgBurn installation defaults to installing things you probably don't want installed on your system in the form of extra Internet browser toolbars or may make other adjustments to your browser.  You don't want to install any of that so you have to pay attention during the installation.

When clicking through the installation screens be sure to pay attention to the screens and always choose a Custom install and UNcheck the following (or any other things like it):

UNcheck:

Install the AVG toolbar and set AVG Secure Search as my default search provider

Set AVG Secure Search as my homepage and newly opened tabs

Choose custom installation again and UNcheck the following:

Uncheck:

Install QuickShare

There could be other things too.

Here are some instructions for ImgBurn:

http://forum.imgburn.com/index.php?showtopic=61

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.

Remember:  You did not boot on your hard disk - you booted into the Hiren's desktop.

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:

cmd

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  /r  it more than once.

When the chkdsk runs clean, remove the CD and restart your system.