How to check if a windows form is already open, and close it if it is?

maybe this helps:

FormCollection fc = Application.OpenForms;

foreach (Form frm in fc)
{
//iterate through
     if (frm.Name == "YourFormName")
     {
         bFormNameOpen = true;
     }
}

Some code in the foreach to detect the specific form and it could be done. Untested though.

Found on http://bytes.com/topic/c-sharp/answers/591308-iterating-all-open-forms

I know I am late... But for those who are curious... This is another way

if (Application.OpenForms.OfType<UpdateWindow>().Count() == 1)
    Application.OpenForms.OfType<UpdateWindow>().First().Close();

UpdateWindow frm = new UpdateWindow()
frm.Show();