Abstract: An advertising system to be used with personal computers which enables sponsors to present advertisements or commercials to a user during periods of waiting-time which are inherent in normal computer use. A segment of a software product contains one or more sponsors' audio, visual, or multi-modality messages. The advertising system chooses one of these messages and presents it to the user of the computer during the times that the user is not normally able to use the keyboard of the computer because information is being loaded up or sent out. Such times occur during the start-up of a program or during the sending of information from the computer to a peripheral device such as a printer, modem, or fax. The advertisement, or sequence of advertisements, may be chosen based upon the amount of time which the computer will need to achieve a task before being ready for new input from the user.