How do I disable the Touchpad for my Inspiron 1564 Notebook ?

Thanks in advance, for any help you can offer. Everytime I'm on the Inspiron 1564 and I happen to brush up against the touchpad, the cursor goes all over the place. Can someone please tell me, how to  disable the Touchpad for my Inspiron 1564 Notebook ? (I have a wireless mouse connected when I'm working, as I don't like touchpads). Thanks ! Elena