C#

namespace ThisProg
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            form = this;
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            textBox2.Text = "Initialising.....";
            Refresh();
            button1.Enabled= false;
        }
        public static void FinishOff(int ErrorLevel)
        {
            button1.Enabled = true; // this line gives error CS0120 An object reference is required for the non-static field, method, or property 'Form1.button1'
        }
        private void button1_Click(object sender, EventArgs e)
        {
            System.Environment.Exit(1);
        }
    }
}