Running a command when an alert is tripped?

I have Nagios running on an Ubuntu server. Among other things, it’s monitoring my domain controller’s (DC) disk usage. It sends a warning alert when that usage exceeds 85% and a critical alert when it exceeds 90%. Is it possible for Nagios to cause the DC to run a local command when one of those alerts is triggered? If so, how can I do that? (The DC is running Windows Server 2003 Std.)

Also, I have Nagios monitoring a number of Ubuntu hosts as well. Is it also possible to do the same thing with those? If so, is the procedure the same? Windows and Linux hosts use different reporting apps (i.e. NSClient++ versus NRPE), so I’m guessing the procedure might be different.

Any info you guys may have on this would be greatly appreciated!

look for event handlers in the docs. on other linux vboxes it should be possible to make it work… on the win box i doubt it.