My 17" MacBook Pro mouse button was sticking. I initially thought it was dust or dirt of something but later during a presentation, my MacBook just shut down instantly at about 70% charge.
It turned out that the battery has swollen and was pressing against the bottom of the trackpad causing the button to appear stuck. A cell had failed which caused the instant power loss once the power dropped below 70%. I went to the Apple store to buy another battery and much to my surprise, they replaced the battery with a new one for free. No apple care and the macbook pro was 2 years old ish. Very cool. System is working fine now with a brand new replacement battery. The trackpad button is back to normal also.
