private void process()
{
btnCreate.Invoke((MethodInvoker) delegate { btnCreate.Enabled = false; chkGroup.Enabled = false; });
}
Thread create = new Thread(new ThreadStart(process));
create.IsBackground = true;
create.Start();
You have to pass a delegate to the Thread object, which is of type ThreadStart. Then for updating the UI you have to update it on the UI thread, using the Control.Invoke method.