Lately the left side of the space bar on my 15inch Aluminum Pbook (where my thumb has been hitting it hundreds of times a day for a year and a half) has started not responding. It's like the sensor underneath is worn out or something. Does anyone have any suggestions for fixing this that wouldn't require me being without it for days while it's in the shop? I literally use this thing about 12 hours out of every day and can't afford to go even a day without it! Any thoughts would be appreciated.