Corrupt Registry Key .dvr-ms in HKCR Preventing SP2 Install

You might try installing this update, and see if it corrects your problems installing SP2:

Windows XP SP1 Update: Watch TV Shows Recorded by Media Center PCs on Other Windows XP PCs
http://www.microsoft.com/downloads/details.aspx?FamilyID=fb4c2c2e-60ea-4ed9-bc68-e93c9e65c58e&displaylang=en

If that doesn't work, you could always try exporting the registry key, then delete it, and see if you can install SP2.  Then add the exported key back after you install SP2.

XP Service Pack 2 Install Problems
http://support.moonpoint.com/os/windows/xp/xpsp2-install-problems/

You receive an "Access is denied" error message when you try to install Windows XP Service Pack 2 or Windows Server 2003 Service Pack 1
http://support.microsoft.com/default.aspx?scid=kb;en-us;873148

Thanks Sage. I'll start trying them and report back.

Thanks Crash but this looks like a format job. I had tried some of the above but absolutely no luck at all. It won't be forced open by anything. Won't give me access to change permissions, export or delete in safe or normal mode. Any last ideas before I pull the plug?

Fixed it. I used Ad-Aware and Panda 2008 to clean it and the source of the problem appears to have been a file sharing app that used Flash to get control of the dvr-ms key. After completely eliminating the spyware that caused it to be locked, follow these steps.

- login as a user that has full admin rights (but is not the admin).
- add Administrator to the those who have full editing rights (look in the Advanced tab). I noticed that there is a complete lack of information in the fields.
- Restart and login as the Administrator. In my case I was able to open the key and the install of sp2 ( although slow) was successful as were all subsequent updates. Logging out and back on as Administrator would probably work but isn't the step I took.

Hope this helps somebody else. Odd ticket

Since you solved this yourself, post a zero point question in the Community Support topic, and ask them to delete this question to get your points back:

https://www.experts-exchange.com/Community_Support/