Our desktop team has finally started deploying Windows XP Service Pack 3 to corporate computers. Their silent installation package kept failing on my laptop. I finally ran the installer manually, and found it was failing with the following error:
Setup cannot copy the file winhlp32.exe
I checked the NTFS permissions, and found that Everyone was denied access to the C:\Windows\Winhlp32.exe file. I logged in with administrative access, removed the deny permission, and SP3 installed successfully.
Turns out that I had implemented this change in file permissions as a workaround to the Help Keypress Vulnerability in VBScript enabling Remote Code Execution, detailed in this Technet Blog post. It’s funny, the things I forget I do to my system to try to deal with security vulnerabilities because I can’t update patches on my own machine.