Question

I have 2 forms: Form1 and Form2. I opened Form2 using:

Form2 newForm2 = new Form2(this);

And now I want to access some variables or methods from Form1 that are set in public like: public int counter;

But when I try this from Form2 it gives me an error:

Error 4 'System.Windows.Forms.Form' does not contain a definition for 'StartGame' and no extension method 'StartGame' accepting a first argument of type 'System.Windows.Forms.Form' could be found (are you missing a using directive or an assembly reference?)

Edit:
In form 1:

Form2 newForm2 = new Form2(answer, button3, button4, button5, button6, this, fiftyfifty, web, change);
newForm2.Show();

In form 2:

Form originalParent;
public Form2(int answer, Button button3, Button button4, Button button5, Button button6, Form parentform, int fiftyfifty, int web, int change)
{
    InitializeComponent();
    originalParent = parentform;
}

and I’m trying to access this like originalParent."public Method here" and it gives me that error.

Answer 1

Your Form2 constructor is defined to get a generic Form as parameter in the constructor.
You need to get a form of type Form1, so change your Form2 constructor to:

   private Form1 originalParent;
   public Form2(
          int answer, Button button3, Button button4,
          Button button5, Button button6,
          Form1 parentform, int fiftyfifty,
          int web, int change)
   { 
       InitializeComponent();
       originalParent = parentform;
   }