Lost of cookies!!! help~~~

Question

i have a login form.. when the user login, i'll store his/her user ID in a cookie... like this: response.cookies("UserID").value i do not allow user to enter into any other pages in my system without first logging in... therefore, i put this codes in my page_load on every other pages in my system... if request.cookies("UserID").value = "" then response.redirect("Logout.aspx") end if In other pages of my system, i've also used cookies to store other information in order to keep track of the user status... i've delete some cookies in these few pages but i'm very sure i've not delete my "UserID" cookies nor i've reset the value... i merely request it only... the problem is somehow after i've log in, and when i go into my other pages, it will suddenly redirect me to Logout page.. i know this is because my request.cookies("UserID").value = "" but i did not delete this cookies or touch it.. i merely request it only... does anyone know y? it has been giving me alot of trouble.. is there someting i shouldnt do or wad?