An image forming device includes a web server, and serves applets to a communicatively coupled computer. The applets execute on the computer, and control one or more operations and/or monitor one or more conditions or sensors in the image forming device. An applet may provide detailed instructions to the computer user as a diagnostic program executes on the image forming device. A list of available applets may be served to the computer, and one or more applets served in response to a user's selection from the list. A decision tree may be served, and one or more applets served as the user advances through the decision tree. Serving the diagnostic applets from the image forming device alleviates the need for a field repair technician to carry a large suite of diagnostic software to diagnose and repair a plurality of models, years, and configurations of image forming devices.