Accidentally Removed Permissions for the XP SP3 Registry key HKEY_CLASSES_ROOT! Workaround Please!

Question

This is Praveen and I am using Microsoft Windows XP SP3 Build 2600. I had problems with using Microsoft Office 2010. It was keeping on saying, "Please wait while windows configures Microsoft Office Professional Plus 2010".

After seeing this link: http://social.answers.microsoft.com/Forums/en-US/outlookcontact/thread/6e9c3f2e-010a-4b74-b433-0c41548ee468?prof=required I thought of giving the Registry Key: HKEY_CLASSES_ROOT, full access permissions for Everyone. I went to the registry, right-clicked on HKEY_CLASSES_ROOT and clicked on Permissions. I added Everyone and gave Full Control to the ACL and clicked on Apply. Also I checked "Replace permission entries on all child objects with entries shown here that apply to child objects." After a long time, it said with an error, cannot replace for few entries. Now, the key, HKEY_CLASSES_ROOT has no access to any user. My system is not starting up.

Some of my friends asked me to try the Last Known Good Configuration. Even that did not work out. When I tried to open in the Safe Mode, I got only one driver to load and even that didn't load well. Another friend suggested me to put the Setup disk and reinstall the OS. I tried that and after completing the "Installing Device Drivers" part, when it started "Installing Network", the system is getting restarted. Now, the setup is also half way through and even if I open in Safe Mode to try System Restore, it popped up a message saying, "Setup cannot run under Safe Mode. Setup will restart now." and the system is restarting.

All my official files and my software, which I developed for Registry Security, resides in my system now. I am unable to access the system and I want it to be working to submit the project, as the deadline is this week. I had no better solutions from elsewhere. Can anyone please help me out with this issue. If it is possible to open the registry editor's stored file from another system and restore the access permissions, I hope it would solve the problem. Please do help me.

Thanking You,
Praveen.

Answer 1

Use this boot CD to access the registry offline, see if you can edit permissions, I have used this to modify Keys, Values and Data, but have not tried changing permissions, hopefully it will work for you.

http://www.pcregedit.com/regedit_guide.html

Otherwise do a manual registry restore

A. Connect your hard drive to another computer, as a secondary drive or use a usb adapter or enclosure and boot into windows. If you can see your data on the drive, back it up Now, then follow the rest of these instructions.

B. Open Windows Explorer. Click on Tools|Folder Options|View. Check the box beside "Show hidden files and folders". Apply your change.

NOTE D: may not represent the hard drive you connected to your PC, it may be E: or F: or G:, it all depends on how many other drives (including cd/dvd) you have in your PC, So subtitute the appropriate drive letter in the instructions below.

C. Navigate to the D:\System Volume Information folder. You will see a folder named something like _restore{.........} the dots represent an alpha-numeric sequence. In this folder you will see folders named RP0....RPnn. Find the one with the highest number. These are your System Restore points. In the highest numbered folder you will see a folder named snapshot. In this folder are registry hive files which you need to recover your system:

_registry_user_.default _registry_machine_security _registry_machine_software _registry_machine_system _registry_machine_sam

D. Create a subdirectory; i.e, D:\Windows\TMP. Copy these files to the TMP subdirectory. Rename them:

default security software system sam

Note Be sure to lose the period (.) in the file named _registry_user_.default

E. Delete the files in the D:\windows\system32\config subdirectory with the same names.

F. Copy the D:\windows\tmp files to the D:\windows\system32\config. subdirectory.

G.Put your drive back in its original system. Your system should start normally. If you get the same error repeat the procedure and choose another folder ( RPnn) (next highest number). You can repeat this procedure choosing lower RPnn numbers until you get it booting again

If you are denied access to any folders you will have to take "Ownership" of the folders first. http://support.microsoft.com/kb/308421

Answer 2

If you work is in non system drive, meaning if OS is installed in C:\ and your work is in D:\ or any other drive, then you can safely go for full re-installation. You won't lose your data.