[Ent]

I want to make a pair of programs (which have to be different programs, not different forms of the same program) such that I can cause one to run a few lines of code in response to a signal from the other. Does anyone know how I can do this?

[-Fabez-]

Use My.Application.CommandLineArgs to pass a signal between the two programs. So you could use ProgramName DataToPass1 DataToPass2, etc.

[Ent]

Sorry, I meant to communicate between two running programs.
For the record I think I've found the answer in the process class--make a process in one as getprocessesbyname(process2name) and then you can close process 2, send standard input, and recieve standard output / errors.