Please be more specific. What exactly do you want to monitor on your Windows servers?
The Splunk Universal Forwarder is capable of monitoring many aspects of Windows systems, but we'll need to know more about your needs to give a good answer.
For example If server is down we need the alert.
Finding something that is not there is not Splunk's strong suit. See this blog entry for a good write-up on it.
https://www.duanewaddle.com/proving-a-negative/