Question: I'm a little confused... 

When I log into the main SharePoint web interface (SharePoint 2007) I'll see a specific user under People and Groups.

Then if I log into Central Admin > Shared Services > User Profiles and Properties > View User Profiles and attempt to search for that user I can't find it.

How is that possible.. shouldn't all SharePoint users be searchable in the View User Profiles section?

Thanks

Answer: 
Yes you can certainly invoke a .exe file using C#. You would use the Process.Start command from the System.Diagnostics namespace. Remember all servers that run this code will need a copy of the exe in the location you specify to run it from.

<http://msdn.microsoft.com/en-us/library/system.diagnostics.process.start(v=vs.110).aspx>
No, but if its an activeX component you can call it through javascript, if you are sure that all the users are running IE. 

If you should call the exe, it should be on the server and then with a lot of hacks you could access the client computer if its on a network where you can control the security.. Not a very clean solution that I would recommend..