Hi,
is that library contained any forms.if so then add this method in your application in class
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
if that library doesnt have any forms then add a form and call it.
One more thing you need change prorperties of the project
just right click on the project and in the properties change OutPut type to "Windows Application" From "Class Library"
All the best......