Create a Windows Desktop Customer Reminder App for Retail Business

This would be a windows desktop app that serves as a birthday, anniversary and event reminder software for a retail Pharmacy business. Information added would include first name and surname, email address, phone number, birthday, anniversary, customization event (with a + sign). It also has a section to add notes for every event. The outlet has multiple locations, so i would want a dropdown box where the person entering the customer details could choose the location he/she is at. The location could be edited in a separate box to add or modify location, which would now appear in the drop box. And users must login with user name and password. These users are assigned access levels by the admin. 3 user levels- Admin, read/write and read only. Read only cannot edit already saved data, cannot export and cannot delete. Read only users can only add new data or read and click on executed tasks. There would be an option to get reminders on the desktop, with intervals on when the reminder would come. There should also be a box to tick if the reminder has been executed or not, on which case it dissappers from the desktop, but it is still in the record incase i would want to pull all data. Also, the folder should be shareable folder for multiple PCs in a LAN. And data could exported or imported via xls or csv format. If should have a friendly simple user interface as the info is meant to be filled while one is in-front of the customer quickly. Also there should be a drop down line after customer's name showing the location from which the name came from. These locations are already pre-filled or one could add new locations.