Program reentering closed form

    public static Form nextForm;

    private Company company = new Company();

    public LoginDAL loginDAL = new LoginDAL();

    public CompanyDAL companyDAL = new CompanyDAL();

    public frmController()
    {
        InitializeComponent();
    }

    private void frmController_Load(object sender, EventArgs e)
    {
        backColor = this.BackColor;
        foreColor = this.ForeColor;
        lblCompanyName.Text = GetCompanyName();
        this.Show();
        if (company == null)
        {
            MessageBox.Show(
                "An error has occurred accessing database -\n" +
                " contact system administrator", "Database Error",
                MessageBoxButtons.OK, MessageBoxIcon.Error);
            Application.Exit();
        }
        else
        {
            apUser = new AccountProUser();
            Form login = new frmLogin(this);
            login.ShowDialog(this);
            if (apUser != null)
            {
                Form menu = new frmMenu(this);
                nextForm.ShowDialog(this);
            }
            else
            {
                Application.Exit();
            }
        }
    }

    private string GetCompanyName()
    {
        company.FirstName = companyDAL.GetCompanyName;
        return company.FirstName;
    }
}

    public partial class **frmMenu** : Form
{
    private List<apallowablemodules> allowableModules = new List<apallowablemodules>();
    private List<apmodule> lstMenuOptions;

    private Form nextForm = new Form();

    public frmMenu(frmController frmController)
    {
        InitializeComponent();
        this.CenterToParent();
        this.BackColor = frmController.BackColor;
        this.ForeColor = frmController.ForeColor;
        UIMenu uiMenu = new UIMenu();
        lstMenuOptions = uiMenu.GetMenuOptions();
        FlowLayoutPanel flp = uiMenu.SetupMenu(lstMenuOptions, this.ToString(), true, "Main Menu");

        foreach (Button button in flp.Controls.OfType<Button>())
        {
            switch (button.Text)
            {
                case "Accounts Payable":
                    {
                        button.Click += btnAccountsPayable_Click;
                        break;
                    }

                case "Accounts Receivable":
                    {
                        button.Click += btnAccountsReceivable_Click;
                        break;
                    }

                case "General Ledger":
                    {
                        button.Click += btnGeneralLedger_Click;
                        break;
                    }

                case "Inventory Control":
                    {
                        button.Click += btnInventoryControl_Click;
                        break;
                    }

                case "Payroll":
                    {
                        button.Click += btnPayroll_Click;
                        break;
                    }

                case "Sales Analysis":
                    {
                        button.Click += btnSalesAnalysis_Click;
                        break;
                    }

                case "Maintain AccountPro":
                    {
                        button.Click += btnMaintainAccountPro_Click;
                        break;
                    }
            }
        }
        flp.Location = new Point(
            (this.Width - flp.Width) / 2,
            ((this.Height - flp.Height) / 2) - 70);

        this.Controls.Add(flp);
        this.ShowDialog();
    }


    public void btnAccountsPayable_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmAccountsPayableMenu();
        this.Close();
    }

    public void btnAccountsReceivable_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmAccountsReceivableMenu();
        this.Close();
    }

    public void btnGeneralLedger_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmGeneralLedgerMenu();
        this.Close();
    }

    public void btnInventoryControl_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmInventoryControlMenu();
        this.Close();
    }

    public void btnPayroll_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmPayrollMenu();
        this.Close();
    }

    public void btnSalesAnalysis_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmSalesAnalysisMenu();
        this.Close();
    }

    public void btnMaintainAccountPro_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmMaintainAccountProMenu();
        this.Close();
    }

    private void btnExit_Click(object sender, EventArgs e)
    {
        this.Close();
    }

    public override string ToString()
    {
        return "MainMenu";
    }
}

public partial class **frmInventoryControlMenu** : Form
{
    private List<apallowablemodules> allowableModules = new List<apallowablemodules>();
    private List<apmodule> lstMenuOptions;

    public frmInventoryControlMenu()
    {
        InitializeComponent();
        this.CenterToParent();
        this.BackColor = frmController.backColor;
        this.ForeColor = frmController.foreColor;
        UIMenu uiMenu = new UIMenu();
        lstMenuOptions = uiMenu.GetMenuOptions("Inventory Control", frmController.apUser);
        FlowLayoutPanel flp = uiMenu.SetupMenu(lstMenuOptions, this.ToString(), false, "Inventory Control Menu");


        foreach (Button button in flp.Controls.OfType<Button>())
        {
            switch (button.Text)
            {
                case "Maintain Inventory":
                    {
                        button.Click += btnMaintainInventory_Click;
                        break;
                    }

                case "Receive Inventory":
                    {
                        button.Click += btnReceiveInventory_Click;
                        break;
                    }

                case "Print Pick Tickets":
                    {
                        button.Click += btnPrintPickTickets_Click;
                        break;
                    }

                case "End Of Period Processing":
                    {
                        button.Click += btnEndOfPeriodProcessing_Click;
                        break;
                    }
            }
        }
        flp.Location = new Point(
            (this.Width - flp.Width) / 2,
            ((this.Height - flp.Height) / 2) - 70);

        this.Controls.Add(flp);
        this.ShowDialog();
    }

    private void btnMaintainInventory_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmMaintainInventory();
        this.Close();
    }

    private void btnReceiveInventory_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmReceiveInventory();
        this.Close();
    }

    private void btnPrintPickTickets_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmPrintPickTickets();
        this.Close();
    }

    private void btnEndOfPeriodProcessing_Click(object sender, EventArgs e)
    {
        frmController.nextForm = new frmEndOfPeriodProcessing();
        this.Close();
    }

    private void btnExit_Click(object sender, EventArgs e)
    {
        this.Close();
    }

</apmodule></apallowablemodules></apallowablemodules></apmodule></apallowablemodules></apallowablemodules>