What you use depends on the other program and what it provides for external control. To simply start another program, you can use the System Exec function on the Communications palette. A more sophisticated approach would be to use ActiveX if the other program has such an interface. The ActiveX functions are also on the Communications palette. There are shipping examples for ActiveX and Excel. There's also DDE which is an old, obsolete method. The functions aren't on the palette but they are in vi.lib\plateform\dde.llb.
