How to monitor a folder for changes, and execute a command if it does, on Windows?

I've had good success with an old program called Log Monitor. It's ancient, and long ago abandoned. But it serves the purpose pretty well.

http://www.freeware-guide.com/download/index2.html

I have created a simple utility for this purpose: https://github.com/benblamey/when_changed

usage: when_changed (file path) (command) (optional-parameters)

e.g. when_changed C:\somedir\foo.txt myapp.exe bar wibble 123

With .NET watchfolders this is really easy to code. I'm sure someone have done such a program.

Just found this gem for you http://www.guidingtech.com/9861/automate-folder-actions-windows-watch-4-folder/