Small program for customer database

I need a small program for registering customers to database and keep control of notes etc. on each customer. Ability to add, edit and delete customers. Doublet check. Emails have "mailto:" to easily write an email to customer Phone numbers "callto: to easily dial up customer via phone central Notes/history with this client. It needs to be very simple with big buttons and smooth design. We want copyright. ## Deliverables I would also like to be able to set deadlines and get a warning - so really this means a calender.