Im trying to open a new windows form by clicking in a menustrip item. Its not the first time I make that but now it doesn't work and I dont know why.
Here it is the code I have:

private void aboutToolStripMenuItem_Click(object sender, EventArgs e)
            AboutBox about = new AboutBox();

        private void helpToolStripMenuItem_Click(object sender, EventArgs e)
            HelpBox helpbox = new HelpBox();

About box works perfectly but help box don't. I proceeded the same way. Here it is the Solution Explorer printscreen:

I donk know if it is important. Now Im using Visual Sudio 2008 but I started this project with Visual C# Express version. I thoght it was a limitation of express version but in visual studio I have the same result.

error CS0246: The type or namespace name 'HelpBox' could not be found (are you missing a using directive or an assembly reference?)

Any suggestions?
Thanks in advance!

Check the code of HelpBox.cs. Im assuming that the name of the partial class inside that file may not be matching with the filename - HelpBox.cs.
Maybe the name of the form was changed after it was initially created but the class name was not changed.

Thanks Jatin.
I didnt remember that I had changed "default namespace" in project options so every new windows forms was created with the wrong namespace. Now its working!