Is it possible run XWiki as a Windows Service??

XWiki is just a web application that's supposed to run in a servlet container. XWiki can't run as a service, but some containers can.

This means that it's not easy to run the standalone package as a service, but you could install Apache Tomcat, for example, configure it to run as a service, and then import XWiki into Tomcat.

A quick Google search led me to this:
http://tomcat.apache.org/tomcat-7.0-doc/windows-service-howto.html

For how to install XWiki into a servlet container, see the .war installation guide.