Diseases of the heart and blood vessels, such as heart attacks and strokes, are very common and can lead to severe disability or death. Changes in the body leading to heart attacks and strokes usually develop over decades as a result of smoking, diet, and lack of exercise, obesity, diabetes and high blood pressure. Changes in lifestyle and diet can significantly reduce the risk of heart diseases. General Practitioners invite 40 to 74 year-olds who have no known heart disease to take part in the NHS Health Check, which measures each person's individual risk of developing a heart attack or stroke and encourages them in a face-to-face meeting to take part in programmes to help them to give up smoking, lose weight etc. where necessary. In this new clinical trial the investigators will test whether computer-tailored electronic (e)-coaching via email and the internet can help people make the necessary changes in their lifestyle to reduce the risk of heart attacks and strokes.