(American English base) For computer programs, we often use the word 'open' to describe the action of starting the program (this may originate with Windows, where programs are given verbs we might also use on a literal window, like close). We might say "go to Skype" if it's expected that you've already opened the program and it's in the background somewhere. To 'run' a program is used, but often in more technical circumstances, particularly when the program itself requires very little user interaction, such as a predefined script. Additionally, for programs which must be logged in to, such as Skype, we may simply substitute the verb 'open' with 'log in to', as logging in will require opening the program and is a more specific and involved task than simply opening the program, which can be inferred by the need to log in.