How to Correct this error

this is the full code in login button click,and the eeror is coming on
myCookie.Value = username1.Text + '-' + roleid2;
and the error is
Object reference not set to an instance of an object.

myCookie = new HttpCookie("video");
myCookie = Request.Cookies["video"];


if (myCookie != null)
{

//string line = myCookie.Value;
//string[]array1=line.Split(',');

//Response.Write(array1);
}
else
{

Response.Write("not found");
con.Open();
System.Security.Cryptography.MD5CryptoServiceProvider x = new System.Security.Cryptography.MD5CryptoServiceProvider();
byte[] bs = System.Text.Encoding.UTF8.GetBytes(passwordtxt.Text);
bs = x.ComputeHash(bs);
System.Text.StringBuilde ...