Please don't spread misinformation on things you know nothing about. This is a very well studied field, where people are making very reasonable attempts at correcting for Earth biases. For more information I suggest reading information available at websites such as this:

http://astrobiology.nasa.gov/

We don't know what else life looks like, so we can't really look for it.

I tend to agree and think its a bit unfair to downvote this. Why must life exist with organics molecules?

Who would have expected arsenic based life (I don'think many would call this organic): http://www.washingtonpost.com/wp-dyn/content/article/2010/12...