ALT Key Stuck, D610, XP SP2

Dell Latitude D610
Windows XP Professional, SP2

The ALT key on my laptop keyboard is stuck which has rendered my PC almost useless e.g. the File menu is constantly flashing, double clicking an icon opens its properties etc. I'm unable to enter text via the keyboard as every letter is interpreted as ALT and the letter.

The Dell system diagnostic test indicated: 2C00 : 0421 Stuck key detected. Keyboard continuously transmitting a scan code.

As I'm about to replace this laptop in a few months I don't want to go to the expense of repairing the keyboard.

I have a BlueTooth keyboard that I'd like to use, however the built-in keyboard seems to work in parallel with the BT keyboard i.e. it is not disabled, so all the problems remain.

Is there a way to disable to laptop's keyboard so that only the input from the BT keyboard will be processed? I've used a compressed air cleaner on the keyboard, but the problem remains.