On a schedule basis? Hm, you can create test that always have the same result (e.g. ping local host). Assign schedule that you need (e.g. 01:00am every monday). Create alert profile with single action "Reboot remote system", set "Repeat: until status changes" option and assign this alert profile to the test. So, HostMonitor will execute action every time the test is performed.
I would recommend scheduling an AT job with the Resource kit tool SHUTDOWN.EXE. That way you don't have to rely on an external system to reboot that server.