need help with page_load

Hi

I am new to development so i hope my question is not silly for you.I have developed a web page and there is user login part in an update panel.I check the session["status"] on page load and if it is true change the visibility of update panel to false and make the "welcome ..." lable visible. It works perfectly at first time but after page changing update panel became visible with the input textboxes again! In debug I have observed that the code do not enter the page load..While the screen that update panel and input textboxes are visible when I hit the (F5) to refresh the page update panel becomes invisible and "welcome ..." label becomes visible..So I thougth that it is a certain problem of Page_Load...

Is there any suggestion or solve method for this? Is my method for logging in is wrong for Ajax?

Thanks for concerning

Help needed please,it is urgent:(