403 Forbidden after Windows update

[CJ Dennis]

Hi! I am running Apache 2.4 from Apache Lounge on Windows 7. Last Friday (12 Oct 2012) I could access web pages on http://localhost/ but at some time in the morning it stopped working with:
"Forbidden
You don't have permission to access / on this server."
(normally it says "It works!")

I rebooted the PC and noticed that Windows was installing updates. Apache is running fine but not serving any pages (except above 403 error message). I changed nothing at all (no .conf files, no .htaccess files, no file permissions, etc.) between it working and not working. The computer was not rebooted before the problem started. Any ideas how to fix it?