VS 2008 C# Screen Lockups

I have a series class libraries that I have added to an external application that present various screens to the users. About 2 or 3 times a month all screens become unresponsive and the solution is to leave the application and come back in. It is virtually impossible to repeat what is causing this, I have tested all the screens individually and inside each program I have error capture routines that never return anything, the programs simply do not run. What kinds of traps can I use to determine why they fail to fire when called? I have attached a sample of my code to show how I invoke forms.

public void ViewAppliedDocuments(object sender, EventArgs e)
        {
            if (ViewAppliedDocumentsForm == null || ViewAppliedDocumentsForm.Created == false)
            {
                ViewAppliedDocumentsForm = new frmViewAppliedDocuments();
            }

            ViewAppliedDocumentsForm.Show();
            ViewAppliedDocumentsForm.Activate();
            ViewAppliedDocumentsForm.Focus();
        }

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