This whole thread needs to take a step down from Science Fiction and do some research.
1st - That whole inorganic/organic thing. It can't be living because its not organic? We invented the stupid word, lol. Means nothing, its a convenient way for us to classify between different kinds of molecules that is quickly becoming out-dated (perhaps because of statements like that).
2nd - There is no carbon outside our galaxy? Say whaaaaaat? The theory (now anyways) is that stars collected elements, performed that beautiful reaction known as fusion for billions of years, then exploded. Since everything was mostly protons (Hydrogen) before stars formed, it was the exploding starts that distributed all the other elements. We are all made of stardust, from one time or another. Since a galaxy is a spinning collection of starts, it would be odd to say that other galaxies didn't have carbon, it seeming to be a fairly common element as far as star-byproducts go.
3rd - Silicon based life. Life is essentially a result of the (some would say spontaneous) assembly of smaller molecules to form bigger molecules. Over time, with the right conditions, life as we know it got pretty complex. Think back to when everything must have just been a bunch of proteins, or a floating strand of RNA...lots simpler. It might even have happened randomly! We call it self-assembly when its really simple. Mix the right things together under the right conditions, let 'em stew for awhile, and bam, something way more complex then its component parts forms! I recently read in one of the science journals (maybe Scientific American) that Silicon-based self-assembly has already been proven possible. So, if self-assembly is possible, you just need to have a series of more-or-less ideal conditions for a very long period of time and a bit of shaking/stewing to get something that might resemble life. Theoretically, we already know it can happen. An old episode of the original Star Trek is the first thing I know of to have made that silicon-based life => 'rock men' connection. Less rock men though then rock blobs.
4th - Trolls. Ignore them, lame.
5th - Aliens. Given the size of the universe, it is statistically inconceivable that life didn't already happen somewhere else. Whether its happening now, though, whether it is as intelligent as us, or more-so, whether it is close enough for us to reach in a human life-time...all of these we don't know. We can guess and hope and make predictions, but sadly we don't have enough information to make really accurate ones. We're working on it.
6th - What will aliens look like? Well, we can only look at Earth-life as an example so far. On earth, our DNA has been a prime factor in how our bodies our structured. Given the way we reproduce, if you go back far enough, we all have a common ancestor. (Happy flower time, we're all actually brothers and sisters! You, me, and the cow you ate for dinner...) This common ancestor seems to only have had a specific general set of body layouts. For example, all animals have four limbs and a tail (yeah, humans too, re: the tail bone). We all have similar bone structures (some bones just grew bigger or smaller or got re-purposed). We all have two eyes, olfactory, mouth, tongue, etc. You get the picture. Aliens from a different world, IF they were using DNA (I have no idea how likely/unlikely that is) or something similar too it, would have the same type of issues: their evolution would largely revolve around the success of a common ancestor that lived millions of years before they developed human-style intelligence and technology. So take a look at all the weirdest sea creatures you can find and try and imagine what they might look like if they were to hop up on land and start pillaging their world's resources. Thats what aliens *might* look like. They also might look like Klingons, in a bizarre twist of fate, and be horribly offended by Star Trek when they first learn about it.
Hm...hope that covered all the bases and cleared things up. Oh wait...
7th - The whole aliens among us thing. This has been recurring throughout history. Humans 'imagine' up creatures to which they attribute special 'powers' or 'features' and blame for things going right or wrong, or even sending them messages or tasks. It is either one of the most pervasive hoaxes in human history, the most over-looked psychological defect in human history, OR there might actually be some merit to what is going on with that. I kinda prefer the idea of mysterious powers among us, as I don't believe in coincidence, and like the idea behind it. I, however, don't know enough to make anything more then a preferential statement.