How to restart PHP on Windows? Unable to find the socket transport "ssl"

To restart PHP on IIS, you actually need to restart IIS:

Click Start, click Run, type IISReset, and then click OK.

WinR iisreset

Or, more verbose: iisreset inside a powershell opened as administrator - or even inside a Cygwin shell.

For those that stumbled upon this answer and you're running Windows 10 or another version with PHP but you're NOT running any of the usual web server apps (WAMP, ServerDesktop, IIS, etc), open your task manager and you will probably see "CGI/Fast CGI" which is the PHP. Right-click and end task. The app will not go away but instead, restart with your updated configuration.