Apache not starting after recent upgrade of Skype

[gdansk13]

Apache always had problems with Skype - for that reason I always used to start Apache before starting Skype, and all was well.

Half an hour ago I was running Apache & MySQL very nicely. I then started Skype, which forced an upgrade. After that upgrade, Apache stopped and now will not start.

I am running the XAMPP control panel as an administrator in Windows 8.1. I have restarted my computer and confirmed that Skype is not running. But I still get the usual Apache error message every time I try to start it ("This may be due to a blocked port, missing dependencies" etc).

I do not get any errors about "Port XXX in use..."

I have tried changing the port from 80 to 10080 in httpd.conf, restarting XAMPP as an admin, and get the same error.

The only messages from today in the Apache error.log are these, from about the time I installed Skype:

[Wed Dec 06 14:58:33.047506 2017] [mpm_winnt:notice] [pid 10060:tid 428] AH00422: Parent: Received shutdown signal -- Shutting down the server.
[Wed Dec 06 14:58:35.085599 2017] [mpm_winnt:notice] [pid 1824:tid 380] AH00364: Child: All worker threads have exited.
[Wed Dec 06 14:58:35.319919 2017] [mpm_winnt:notice] [pid 10060:tid 428] AH00430: Parent: Child process 1824 exited successfully.