Windows Installer 3.1 weird fix!

If you have XP Pro (SP2) and you've tried all the other tips with no joy, the
following may fix your installer as it did mine:

Like a lot of users, I was getting the error #0x80070005 (access denied)
upon each install attempt. Windows Update.log showed another error
#0x80070643 as well.
Also, like a lot of users, I tried renaming catroot2, deleting the
recommended %windir%\SoftwareDistribution files, ensuring registry
permissions were correctly set, and on and on. Nothing worked.

Then, grasping at straws and about to throw in the towel and reinstall XP
from scratch, I luckily took one last look at my Add/Remove list and was
reminded of one of the last updates I had done -- .NET Framework 2. I
decided to try a reinstall (repair option) -- you can get it here:

http://www.microsoft.com/downloads/d...DisplayLang=en

Bingo! Windows Update worked! I had no less than 32 critical updates
waiting for me, plus 4 optional Windows updates.
The KB896344 update refuses to install, despite the "add .bak to
xpsp3res.dll" trick, but since I currently have no 64-bit Windows system, I
can live without this.

I'm at a loss as to why this Windows Installer problem didn't occur right
after I installed the .NET Framework 2.0 update -- I have my Auto Update set
to notify only and I always check the Windows Update site after an update.
The pc ran fine until a few days ago!

HTH...