ne,nu jau nervai nelaiko, kame beda???
public partial class Form1 : Form        //pagrindine forma
    {
        public Form1()
        {
            InitializeComponent();
            Class1 klase = new Class1();
        }

        private void button1_Click(object sender, EventArgs e)    //iki sito 
dar net nedaeina        {
            label1.Text = klase.vardas;
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Form2 forma2 = new Form2(klase);

            if (forma2.ShowDialog() == DialogResult.OK)
            {

            }
        }
        public Class1 klase { get; set; }
    }

antra forma
public partial class Form2 : Form
    {
        Class1 _klase = new Class1();

        public Form2(Class1 klase)
        {
            InitializeComponent();
            _klase = klase;
        }
        private void button1_Click(object sender, EventArgs e)
        {
            _klase.vardas = textBox1.Text;        //----->va cia pastringa 
atseit reikia panaudoto "new" ir t.t.
            Close();
        }
    }

klase
public class Class1
    {
        public string vardas { set; get; }
    }