Did you just install UniFi Controller on Windows, configured it to run as a service but it doesn’t run?
After you installed UniFi Controller it will launch the Controller software which will run fine, but when you go through the steps to allow it to run as a service the UniFi Controller service won’t stay running.
If you look at the server.log in the logs folder you might see the following error
ERROR system - [exec] error, rc=2, cmdline=[cmd, /c, net, start, UniFi]
You probably don’t have Java 64-bit installed.