Getting the client windows Account name and computername

Hi

I am working on a project to identify the windows account name of the visitor,and his computer name if possible.

please do not get me wrong. I do not want to find the the website credentials of the vistor. I need hiswindows account name on his computer.I need theaccount name which appears in windows logon screen when the visitor turns on the PC.

do not mistake it for windows or environment username of the host running the script.

notice that we should get the account name from the visitor browser, not from the host or server.

for example these lines of codes won't solve the problem, they give the server windows username:

System.Security.Principal.WindowsPrincipal p = System.Threading.Thread.CurrentPrincipal as System.Security.Principal.WindowsPrincipal;
string strName = p.Identity.Name;
string first = Request.ServerVariables["AUTH_USER"];
string second = HttpContext.Current.User.Identity.Name.ToString();
string third = HttpContext.Current.User.Identity.Name.ToString();

any idea or help is appreciated,also it doesn't matter which way we are using(for example i heard about aspexec or ...)

Thanks in advance