To execute a program, a computer opens a usage window of a user interface of the program when calling the program. Via the opened usage window, the computer receives usage commands for a usage part of the program from a user, the usage commands being presented during the input thereof in the usage window, or in a usage command window of the user interface. The computer executes a usage action corresponding with a usage command after validation of the usage command, and receives retrieval commands from the user to retrieve additional information. The retrieval commands are presented in a retrieval command window of the user interface during the input of said retrieval commands. Additional information is received from a web server after the validation of the respective retrieval command. The retrieval and output of the additional information is an action different from the usage action. The information window, the retrieval command window, the usage window and the usage command window are different windows.