The virtual remote is only available for use with the Chromecast with
Google TV devices (the oblong ones that come with a physical remote).
You can't use it on any other Chromecast device because they don't have
that same kind of on-screen menu syste...
In the odd chance that you have one, some people have said that a Fire
TV remote will work just enough to get you past that screen. But, as
David said, ordering a replacement from Google is definitely the way to
go.
If you are talking about the button ON the Chromecast device, yes, that
is reset. Here are instructions:
https://support.google.com/chromecast/answer/6254654
No, I"m sorry, there is no way to locate or disable a Chromecast. When
the thief plugs it in it will not be able to find your network and go
into Setup mode automatically. I would suggest that you immediately
change your Google Account Password and t...