The AppActivate method activates an application.
The AppActivate method tries to activate an application whose title is strTitle. If strTitle does not match any titles of the running applications, then the application whose title begins with strTitle is activated. If none of the running applications have a title that begins with strTitle, then the application whose title ends with strTitle is activated. If strTitle matches the titles of more than one application, then one of the applications is arbitrarily activated.
Set WshShell = CreateObject("WScript.Shell")
This VBScript code activates Notepad (assuming that an instance of Notepad is currently running).