How do I clear instrument list?

[Roese]

I have an Agilent N5700 series power supply connected to a PXI Chassis via USB.  I have a control connected to the "Resource Name" input of my driver VI, which gives me a selection to choose from.  "Refresh" is at the bottom of the list.  Anyway, how come reources that are no longer powered on still show up in the list.  I noticed that when I go to MAX, the resources are not listed in the tree. But if I power the resouce on, it refreshes the tree in MAX.  The same when I power OFF the resource. So, I guess my question would be....Is there to make the list in my VI act the same way.  If  resource is not present (powered on), I don't want it to show up in my pull down menu list.

[JÞB]

Its there because the VISA Alias is reserved.  If you look in MAX Tools>>NI VISA>>VISA Options>>My System>>General Settings>>Aliases.  You will see the Aliases reserved for Plug'n'Play devices (By equipment serial number).  You could "Clear" the Alias to get it out of the Resource name pick list until the next time you plug it in.... but thats kind of pointless.  Plug'n'Play (Or Plug'n'Pray as some people say) just works the way it works with VISA.