HKEY_CLASSES_ROOT becomes corrupt

[BradPDX]

This is an odd one. Machine is typical Dell PIII with 512MB RAM, W2K SP4. I use this machine all the time, my own privileges are local administrator.

The problem that started yesterday is this: most things work, but attempting to open certain files causes an incorrect application to open improperly, which then consumes loads of VM until the system halts.

Upon checking the registry, I find that HKEY_CLASSES_ROOT (which should contain all of the extensions used on the system with info, etc.) is now largely full of garbage characters. Only a small number of extensions appear to be correctly registered.

If one then attempts to open Folder Options -> File Types, Explorer.exe will also consume all VM and bring the system down.

I have checked for virues, nothing. Many programs still work fine (MSOffice, Mozilla, etc.) Certain programs now fail completely.

I don't know what caused this, and how best to fix. I have disk images that are a few months old, and things are backed up, and so with a few hours I could get it back. However, I want to understand this better so that it can be prevented or fixed more easily.

I know that parts of HKEY_CLASSES_ROOT are created at each boot, but other than that I am not sure. Any ideas out there?? Thanks!

- Brad

 

[Sival]

Installed anything recently, or made any other software changes?

 

[BradPDX]

I thought about anything that might have been installed, and yes there are some rather ordinary things - but this problem is so odd that if those items were responsible I can imagine that thousands of people would experience this same issue.
Recently installed items:
iTunes 4.1 (works beautifully)
Mozilla 1.5 (works beautifully)

I fixed the problem in a roundabout fashion. First, I used my Altiris Deployment Server to backup my C: partition, leaving D: were it was (D: is my data partition). Then I restored a C: partition image that was captured 1/2003. I then exported the clean key HKLM\Software\Classes from that image to a REG file on my server. Then I restored my funky C: partition, deleted the bad copy of HKLM\Software\Classes and replaced it with the REG file that I had exported from the 1/2003 disk image. It worked; I just need to run installs for a few programs and all is well.

I will now make a point of using my Deployment Server to make registry backups more often!

- Brad