Best guess solution, try this:
protected void Page_Load(object sender, EventArgs e)
{
if (!String.IsNullOrEmpty(Request.QueryString["password"])
txtPassword.Text = Request.QueryString["password"];
}
That will work assuming your URL looks something like this:
http://www.mysite.com/MyPage.aspx?password=bob
Just a thought, passing though a password in a query string makes is visible for the whole world to see. It might be a better idea to store it in the session. Have a read here:
http://msdn.microsoft.com/en-us/library/ms178581.aspx[
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