JustNN is a neural network system for Microsoft Windows. It makes the creation of neural networks easy. It allows the user to produce multilayer neural networks from a grid or from text files and images. The user can produce training, validating and querying files using the facilities in JustNN or using any editor, word processor or spreadsheet that supports text files. JustNN can learn from training data and can self validate while learning. It can be queried from a file or interactively. JustNN can produce txt or csv output and results files.