Windows XP UNSOLVED: Major Windows Registry Error. Whoever solves this is a master!

[WhiteFrost]

SITUATION:
When I boot up my computer, it is all fine. It gets to the XP Login screen. I click on my user icon, it's fine, but after logging in, it shows only the wallpaper and nothing else. The same thing happens when I attempt to log in with Safe Mode, except instead of my wallpaper, it shows a black screen. In both cases, when I say it only shows black screen or wallpaper, I cannot see the Start Menu or task bar whatsoever and of course no icons on desktop. I can however, access Safe Mode with Command Prompt

CAUSE:
I mass changed HKEY_CLASSES_ROOT folder using Regedit and somehow changed all the permissions so that they would all be under SYSTEM having full control instead of Administrators. (I had actually wanted the Administrators to have Full Control)

WHAT I HAVE TRIED:
- I tried to boot up into safe mode, but after login, it gives me a black screen.
- Use Windows XP CD Recovery Console using command CHKDISK /R

THINGS THAT I BELIEVE WILL HELP IN THE SOLUTION:
- SYSTEM has "Full Control" of everything in the HKEY_CLASSES_ROOT folder.
- I can use Safe Mode with Command Prompt and use Task Manager
- Maybe there is a utility that is able to change the permissions in the registry?
- A way to change registry permissions back to administrator using command line?
- Everything in the registry except for the HKEY_CLASSES_ROOT had their permissions changed, so I am 100% sure that the permissions of HKEY_CLASSES_ROOT is the thing that is causing the problems.
-Task Scheduler does not run in Safe Mode, maybe there is a way to boot up with Command Line booting something from the CD?

I really hope that someone can help me with this issue as it is very annoying. I do not want to lose any files on my C: drive so formatting and reinstalling is not an option for me.
I have tried importing a .reg backup file I made before I did it, but it said that it was not valid. When I try to add a key to HKEY_CLASSES_ROOT, it gives me an error:
----
Cannot create key: Error writing to the registry.
----

When I rightclick on HKEY_CLASSES_ROOT in regedit and click "Permissions", it does show that Administrators have "Full Control", but when I click "Add.." it pops up an error:
--------
Unable to display the user selection dialog.
Class not registered
--------

but when I open up the HKEY_CLASSES_ROOT folder with Regedit, many things are gone (all file extensions), which leads me to believe that maybe only the SYSTEM is able to view them as I had accidentally set the SYSTEM to have access to everything in HKEY_CLASSES_ROOT. If there is something that I can do in Regedit to solve this issue that does not require me having to do anything that involves those 2 steps, I will be glad to try it to see if it works.

 

[Me__2001]

format it and start again, dont mess with the registry if you're not prepared to do this in the future

 

[floppybootstomp]

*sigh*

yet another

The answer is, as always: backup

Can I say that again?

Ok

Backup

Windows, is, really, a bit crap.

Not had many problems myself, must admit, but have read hundreds, thousands, of posts like this one

do not rely on the hard drive with your current OS as a reliable permanent data storage system

in fact, don't even rely on other, seperate, hard disks

best form of backup is CD's and/or DVD's, done in duplicate

Best backup for whole OS's is Acronis True Image, to another hard drive or even better another two hard drives

other than that - reinstall

or use, and learn, Linux

and even Linux won't guarantee against a hard drive failure

Life's a **** sometimes ain't it?

 

[AbsoluteKevster]

Do you have a Restore point from before the Registry damage?
Failing that, I'd have a crack at an XP Repair-Installation before losing your OS.

Good Luck!