Winlogon.exe with high cpu usage when checking browser type

Hi I have a .net website(4.0) running normally on server (windows server 2008 R2).
I have added some code to 4 of my pages and published dll using visual studio 2012. After that i noticed that winlogon.exe cpu usage increased to 75%. Before changing dll it was 0% , and if reput old dll back without the new changes in code it comes back to 0%.
These are the only changes i have done to my website (same code for all 4 pages):
On Page_Init, I added this to each page to check if browser used is pad or mobile and if so transfer to corresponding page
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init InitializeComponent() Dim userAgent = HttpContext.Current.Request.UserAgent.ToLower If userAgent.Contains("ipad") Then Server.Transfer("pageTablet.aspx") ElseIf userAgent.Contains("android") = True And userAgent.Contains("mobi") = ...