Launch form

First, i'm sorry my english. I'm a begginer in C#. What i have to do now is very simple, but i try many things and no one work. I have a database who contain the name of all form. These forms can be in differents namespaces. When i click on a menu item in the menu file of the application, i can retreive all information of the wanted form but i just can't launch it! How can i launch a form with the name provided by the database? Thank you