C# calling overridden subclass methods without knowledge that it's a subclass instance

Class Foo
{
    public virtual printMe()
    {
        Console.Writeline("FOO");
    }
}

Class Bar : Foo
{
    public override printMe()
    {
        Console.Writeline("BAR");
    }
}

List<Foo> list = new List<Foo>();
// then populate this list with various 'Bar' and other overriden Foos

foreach (Foo foo in list)
{
    foo.printMe(); // prints FOO.. Would like it to print BAR
}

class Foo
{
    public virtual void virtualPrintMe()
    {
        nonVirtualPrintMe();
    }

    public void nonVirtualPrintMe()
    {
        Console.Writeline("FOO");
    }
}

class Bar : Foo
{
    public override void virtualPrintMe()
    {
        Console.Writeline("BAR");
    }
}

List<Foo> list = new List<Foo>();
// then populate this list with various 'Bar' and other overriden Foos

foreach (Foo foo in list)
{
    foo.virtualPrintMe(); // prints BAR or FOO
    foo.nonVirtualPrintMe(); // always prints FOO
}

foo.printMe(); // prints FOO.. Would like it to print BAR

(Foo)foo.printMe(); // foo can be any derived class of Foo.