I am currently developing an application with VB.NET. I just upgraded from VB6. I have 2 questions:
1) How do I open a form and only one instance of the form. For example, I am using the following code:

Dim frm as New frmMain
frm.Show()

This works fine but I only want the form to open once. If I click this button again, it opens another instance of the form.

2) When I package and deploy my applicaiton, are my users required to have XP or the .Net framework installed on their machines? Can I package and deploy a VB.Net application to run on a machine running Win95 or 98? Is the framework included in the installation of my packaged program?