You're very confused, so the question even does not make sense.
However, if you have more than one form in the same application, you need to link them with form ownership relationship. This helps to conveniently support some UI integrity in terms of form activation. You need to look at the property
you need to set. Normally, your main form should own other forms (which is not so by default). A form should be added using
and removed using
; you can also use the property
Please see http://msdn.microsoft.com/en-us/library/system.windows.forms.form.aspx
Also, consider setting the property
for all owned forms. They will be shown on top of Z-order when a Owner form is shown, not independently. At the same time, the owned form can be sent on top and activated. The ownership only guarantees that no windows of other application will be placed between any forms of yours, which probably is what you require. If one form is send to the top of Z-order, all other related forms of your applications go on top automatically.