Laptop with weird issue.

Hey, has anyone had a similar problem? I have an Asus N61JQ laptop and am trying to reinstall windows on it. When it gets to the enter password screen it starts filling the fields with a character. It acts like a key is stuck on the keyboard. Now have removed the keyboard from the laptop and still it acts like a key is stuck whenever you boot from a rescue cd and load wordpad and any text editor.--it inputs a continuous string of the "+" character. Yet no keyboard is attached. Any idea as to what could be causing this behavior?

Any help would be greatly appreciated.