if your problem is when inserting....then definitely there should be problem in your query....
try this....
cmd = new sqlcommand("INSERT INTO emptable(EMP_NAME)VALUES('"+textbox1+"')", sqlconn);
sqlconn.Open();
cmd.ExecuteNonQuery();
sqlconn.Close();
If the above solution is same as yours....try connecting your connection like....
con = new sqlconnection(@"Data Source = A\SQLEXPRESS;Initial Catalog=empDB;Integrated Security = True");