Hi JL3008:
I don't know of any obvious reason why the .msu installer for KB3185911 (rel. 13-Sep-2016) would not install if Windows Update has not run successfully since March 2016, unless there is some deeper problem we haven't uncovered yet (e.g., corrupted permissions in your Windows registry that prevent correct tracking of installed updates). I re-checked the supersedence chains of both KB3185911 and KB3191203 in the Microsoft Update Catalog and neither has been replaced by a newer update. The most common reasons for a "not applicable" warning are listed in the support article "The update is not applicable to your computer" error when you install Windows updates, and I don't think any of those reasons apply as long as you're using the correct 32-bit installer.
As one last experiment, open your IE9 browser, go to Tools | About Internet Explorer, and check if you have the latest Update Version 9.0.57 (KB3203613). If you have an older version, save the latest 32-bit Vista SP2 .msu installer for KB3203613 (MS16-144: Security Update for Internet Explorer: December 13, 2016) from http://www.catalog.update.microsoft.com/Search.aspx?q=KB3203621 vista to your desktop and run it as previously instructed.
If you get another "not applicable" warning, just an FYI that there is an alternate way to search for KB3203613 if you can't find it when you search your installed updates at Control Panel | Programs | Programs and Features | View Installed Updates. You can open an elevated command prompt (click on the Windows Start button, enter cmd in the search box, right-click on cmd.exe, and select Run as Administrator) and enter the command wmic qfe | find "KB3203621" (with quotes around the KB number) as instructed in the article Get Hotfix Information Quickly with WMIC.
I've done a bit of research on error code 8000FFFF and will post that information for you along with a further suggestion if the KB3203613 update for IE9 won't install.
32-bit Vista Home Premium SP2 * Firefox v51.0.1 * NIS v22.8.1.14 * Speccy 1.30.728
HP Pavilion dv6835ca, Intel Core2Duo T5550 @ 1.83 GHz, 3 GB RAM, NVIDIA GeForce 8400M GS