Disclaimer: yes, I know I should be using newer software on a newer OS, but I haven't had time to update it.
I have a legacy ASP script running on an ancient 2003SP2 server and this morning I did a Windows Update that successfully installed KB2929961 and KB2930275. Later in the day I found out an ASP form was not working. It was giving the error: "asp 0177 : 800401f3" and a line number pointing to a CreateObject("Scripting.FileSystemObject") as the source of the error. I've seen this before but it's been quite awhile and always after doing a Windows Update.
I did the regsrv32 /u scrrun.dll and regsrv32 scrrun.dll thing successfully, but it didn't work - as usual.
Next I ran Procmon.exe from SysInternals to see where the error was and I found it by running the script then stopping procmon. Way too much data, but I searched for FileSystemObject and found that there was ACCESS DENIED on HKEY_CLASSES_ROOT/Scripting.FileSystemObject. Now I remember!
I opened regedit and went to that key. It had Administrators and SYSTEM as read only etc., so I added "EVERYONE" and made it read-only. That fixed it. But then I went back and removed EVERYONE and added just the Internet Guest Account (IUSR_computername) as read only. It seems to work fine - at least until the next Windows Update.
Or until I put the Server 2012 machine in service that's been sitting here for a couple months.