This how to will show how to install the open source software NAGIOS to monitor network devices such as switches, routers, servers, firewall…etc.
The detail instruction for installing WMI is found here
A good detail of installing wmi client and wmi plugin is available at interwebplus.com
Note : if your few of the perl modules were outdated, The check_wmi plugin will not work.
in that case you can use –IgnoreMyOutDatedPerlModuleVersions case.