Mine has the same poblem. I wanted to fix it without taking the whole thing apart and found this video http://www.youtube.com/watch?v=VGdTjKt-cYg
Here's what I did, first find out where the Nvidia chipset is located, for mine it's under the d button, then I heated up the keyboard with a hair dryer, then press firmly with the palm of my hand as in the video, then I took out the battery and put the laptop in the freezer for 1/2 hour. After that it works fine. Probably won't last, we'll see, but at least it starts now and I got all my files saved.
Just wanted to post this hoping it will help someone else!