To find the existing value in MS Acess database

i developing one window application project for like that stock maintenace, here the form will contains one button for registers name and one textbox for user name, first we will give the name in the textbox and then register the register button, if the name is already available in the database means it should be tell this msg in msgbox “already this name available in database” otherwise it should be added to the database…i need this vb.net code for this development process, database used only ms-acess. please try to give this code and help me… i dont know how to give this…