This procedure worked for me with a couple differences:

3. Check (not uncheck) the the box "Close this dialog box when download is
complete"

9. The command returned error "y invalid switch" so I proceed to 10 anyway.

10.5 I rebooted before returning to Update and doing 11.

Note: After completing this update, and a security patch for 1.1 that then
showed up, I was able to also install the Rollup 2 for XP Media Ctr which had
failed earlier and continued on to .Net Framework 2 without any problem.

Rick

"TaurArian [MVP]" wrote:

> installation fails with error code 643
>
> Courtesy of: Pat Walters [MSFT]
>
> Sometimes patches can prompt for the original installation media (asking the user for
> the location of netfx.msi). This can happen when MSI determines that the original
> product has missing or corrupt files, which are not included in the patch package.
>
> Repairing or reinstalling the original product fixes this issue, so in your case, we
> specifically need to repair the .NET Framework 1.1.
>
> If you already have the .NET Framework 1.1 installation package, feel free
> to skip this section to step 9:
> ----------------------------------------------------------------------------------------------------------------
> Microsoft .NET Framework Version 1.1 Redistributable Package
> 1. Please click the following link or copy and paste it into your Internet
> browser address window:
> http://www.microsoft.com/downloads/d...displaylang=en
> 2. Please click the Download button and save it to a directory you will
> remember.
> 3. Please uncheck the box "Close this dialog box when download is complete"
> 4. Click Start
> 5. Click Run
> 6. Type: cmd <Enter>
> 7. In the Command Prompt, type: cd (target directory path)
> 8. Verify you are in the correct directory for this file by typing: dir
> dotnetfx.exe <Enter> and make sure it lists the file.
> ----------------------------------------------------------------------------------------------------------------
>
> Repairing .NET Framework:
>
> 9. Still in the command line, and now in the proper directory, type: del /y
> %temp%\* <Enter>
> 10. Type or copy and paste the following:
> dotnetfx.exe /t:%temp% /c:"msiexec.exe /fvecms %temp%\netfx.msi" <Enter>
> (note: be sure to use the quotes.)
>
> For example:
> dotnetfx.exe /t:%temp% /c:"msiexec.exe /fvecms %temp%\netfx.msi"
>
> 11. Please try to install the update KB886903 from your direct download one
> more time, and let us know if this works out for you.
>
>
> "-Aaron" <-Aaron@discussions.microsoft.com> wrote in message
> news372EC53-DE9E-4CB2-BE5C-3705A58FA52A@microsoft.com...
> >I have tried installing the Microsoft .NET Framework 1.1 Service Pack 1
> > update on windows update, but have received the following error
> > message...0x643
> >
> > Can you help me??
>
>