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How do I Repair My System if the Registry Can’t Be Loaded?

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My system, Windows XP Professional, won’t load. When I turn it on, I get this message, “Windows could not start because the following file is missing or corrupt: \Windows\System32\config\system.” And I don’t have an installation disk. I read some of your material and it looks like I have the i386 folder in the right place but I can’t get to a command prompt. I have a rescue and recovery disc, but the only thing it will do is let me load the original backup created when I bought the system back in 2008, or bring the system back to its original factory state.

I really don’t want to do either of these two things. I researched the problem, and I could repair the five registry files with a series of DOS commands (from a Windows paper) if I can get to the recovery console and then just restore the system to a previous restore point. After reviewing the material, from Microsoft, I think I can do it. But I want and need to upgrade my system so it occurred to me to just buy Windows 8.1 and do a clean install and then restore my backup that I made about a month ago but I’m concerned that I might overlook something.

All of the programs that I use also have to be reinstalled or redownloaded and installed so I’m looking at perhaps hours and hours of work. So I really have two questions. The first one is there a handy informational guide to a clean install that will bring the system back to nearly what it was before but with a brand new system. If I decide to fix the system instead, can I buy a non-OEM installation disk for Windows XP Professional or does it absolutely have to be an OEM disk that is compatible with my machine?

Unfortunately, the file that’s missing or corrupt is actually the system registry or one of the major hives of that registry. On my Windows XP machine, it’s something like 30 MB in size, so it’s not something that you can just recreate with a simple command.

Or is it?

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The registry & backups

That file is actually a core component of Windows itself. It contains the system portion of the registry; the database of system settings and information that Windows uses and keeps track of. There’s no magical command to simply recreate it from scratch. The only real hope is a backup. Now it sounds like you might have one, but there might also be another.

You mentioned that you have a backup from about a month ago. If that’s an image backup – an image of everything on your computer at the time you took it – you could restore that. That would restore everything, including that missing or corrupt file. Alternately, it’s possible that there’s a backup of that file in the same folder. On my XP machine, there’s something called system.sav for example, which is a few days older than the actual system file:

System and System.sav

You can copy system.sav on to system and maybe things would work.

Copying without a command prompt

So, the question you have course, is how to copy it if you can’t get to a command prompt?

One approach is to boot from your original installation media, and if it includes repair/recovery options, you may be able to open a limited command prompt there in which you can perform the copy operation.

If you can’t there’s one not-so-obvious solution: Linux.

If you can download and burn a Linux Live CD or DVD on another machine, then boot your existing machine from that DVD, you may be able to use Linux to perform the copy operation that we’re talking about. It does sort of require learning to do things the Linux way, which is similar but not identical, but it might very well be an option. That’s probably one of the first things I would try.

To be honest, I’m actually a little concerned about why and how this happened in the first place. For example, if it’s a hard disk going bad, whatever fix you put in place might be temporary. If it’s a software issue, just replacing the file from a backup isn’t going to fix the software issue that caused the problem.

Retail versus OEM repair

Now, to answer your two questions: a retail Windows XP disc might work to repair your existing installation. Then again, it might not, but it should at least get you a repair console, if that’s all you’re looking for. At the extreme end, a retail disc will let you reinstall Windows XP from scratch.

An OEM XP disc may or may not work. It’s actually impossible to tell. To stack the deck in your favor of course, you’re going to want to get the OEM disc for that specific computer, or at least from that computer’s manufacturer.

Upgrade

The steps for upgrading a machine such as this to Windows 8 are actually extremely simple.

First, confirm that the hardware supports the new operating system. Windows 8 does place a couple of additional requirements on a CPU that some older machines might not meet. If that’s the case with your machine, you can probably still upgrade to Windows 7.

Second, back up your machine. If you haven’t taken an image backup lately, do so now. Even if you can’t boot from Windows, you can often boot from the backup software’s rescue disc, and use that to make a backup image of the machine. That way you’re certain that you’re not going to lose anything when you perform the following steps.

Third: install the operating system from scratch. That typically means wiping the hard disk, installing only the operating system, and basically getting up to date.

Next, install all your applications from scratch.

And then finally, restore your data either from that backup you started with or from wherever else you happen to save your data.

With Windows XP, you might instead be able to perform what’s called a repair install. That would leave your applications installed while refreshing the operating system. But a move to Windows 7 or 8 from Windows XP does require a reformat and reinstall.

2 comments on “How do I Repair My System if the Registry Can’t Be Loaded?”

  1. Leo,
    My computer has been hacked and most of my applications are not able to load from my desk top.
    I think the problem is the registry.
    Can I repair this through my command prompt and what would the command be.
    Regards,
    John P
    {email address and phone number removed}

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