Normally when you do this in C# you would have done something like this to open a new Form. Is the solution something simular to this ?
Form2 form2 = new Form2();
form2.Show();
Im just curious as to when you would do this on a web page ?
What your looking to do is
Response.Redirect = "http://www.google.com/";
having not used visual web developer i am unsure how you would go about it, but you would not want to post back to achieve this when it can be done in standard HTML unless you needed to perform some validation.
If these are ASP controls which i assume they are, a property is available to you which you can set on each of the buttons along the lines of 'PostBackURL'