I still can't update windows xp home to sp2. I've gotten good suggestions here but so far they haven't solved my problem. I've done what the MS "Access is denied" KB873148 message said to do. I followed ALL its instructions to the letter. I verified that the update was failing when it tried to delete registry key HKCR\vnd.ms.radio. My setupapi.log file showed that it tried and failed to do that twice in succession before it launched into its uninstall routine.

Following KB873148, I then edited the registry (I backed it up to ...my documents... first). I changed the permissions for the vnd.ms.radio registry key that the update routine was trying to delete. I am quite certain that when I clicked File/Exit and saved the modified registry all the permissions for administrators had the "allow" check box selected for "read" and "full control".

That did NOT solve the problem. After I did all that, and reran the *.exe full file version of sp2 which I had previously downloaded, I still got the same "access is denied" error message and I still had the same message in the setupapi.log file afterward.

I'm getting WAY WAY over my head here to suggest this but it's all I can think of:

If the update routine is failing when it tries to delete that single registry key, for whatever reason, is there a way I could edit the registry manually and just delete it that way and see if that works? Assuming I've backed it up, and so forth, of course!

Can anyone suggest a different fix, please?!