Tamil, thank you very much.
But I have tried even that, actualy currently it was: response.redirect ("~/SecondAspPage.aspx") , and I have tried also server.transfer("SecondAspPage.aspx") but even these do not work.
Some other details of the form:
I use session variables on the application, at same time in web config i use cookiless mode (so that it will not save as cookies) and in the form load I clear the session also by calling session.clear().
What it is very strange, on my computer it works perfectly but from some client computers in our network it does not work (what it is strange even for them sometime it works some time it does not without refreshing, could it be someone is playing with some settings in the network, and could that cause that behaviour???). I have tried from home (this is an application that it is used in our internal network but also from outside) and from three computers that I have home it works perfectly.