1)   PA Server Monitor 3.4
PA Server Monitor is a Windows service that monitors the health and availability of Windows servers, network services (on Windows, Linux and other operating systems), and devices. No agents are needed to monitor remote servers. Rich reporting too.

 2)   PA Server Monitor Free Edition 3.1.9
PA Server Monitor has powerful features that are very simple to setup. The Free edition monitors web pages, ping response and the Windows event log, and includes several response actions such as email, reboot, etc. Monitored resource reports too.