Desktop-Reminder is a free program that lets you schedule tasks and set reminders so you won't miss any appointment or other important dates.
It has a nice interface that lets you access most functions immediately. For example, to create a new task, you only need to click on the corresponding icon. A dialog box will appear where you can set all the task's details, such as description, category, date, recurrence, urgency level, and more. You can also set an alarm to warn you in advance. If the task is recurrent, i.e., if you need to perform it for example, every Wednesday at three o'clock, you can set the program in such a way that the alarm sounds all Wednesdays several minutes before the time you need to perform such a task.
The program also allows you to group tasks by categories, such as State (completed or pending), or by day, moth, or year. You can even create your own custom categories. It is also possible to add notes to your tasks, such as the address of your appointment, his or her phone, or any other detail that may be useful to you.
Maybe the main disadvantage of this program is that many of its functions are performed by programs such as MS Outlook, so if you have MS Office already installed, then you may not need this program.