just read this on the Nasa website :
NASA is ending attempts to regain contact with the long-lived Mars Exploration Rover Spirit, which last communicated on March 22, 2010. "
The spirit landed on mars in 2004 for a 3 month mission , but three months became 6 years . They lost contact with the little robot on 22th of march 2010 , chances are big the machine didn't survive the last hard martian winter
Aww poor robot , it kind of looks like wall-e and xkcd made a comic about spirit a while back:
(click for bigger version)