Since I have been a student for the past five years there was no need to file. I was trying to file this year for 2012 and found out someone claimed my son with out consent. I have to mail in my return, but I am wondering how do I find out if someone has claimed him in prior years where I do not claim him due to no income to claim.

You have to wait for the IRS to contact you, which they will, so mail it in. e-file won't let two people claim the same child.
You must have some idea who claimed him? Is there a known father? Is there a court ordered custody, because that is what counts?
You should have filed a tax return to get the student credit, which is substantial. Look into filing for past years. It's not hard.
Tax Information for Students (http://www.irs.gov/Individuals/Students)

His father is not allowed to claim per court order. He lied in 2007 n was ordered to give me the money n was ordered to mever claim him again. How is there student return when I did not work. I only recently worked enough to claim. So how do I make sure no onewas claiming him in previous years. Also how can I take legal action against him if it was the father, since IRS does not disclose that information.

Since 2010, the American Opportunity Credit gives you a $1,000 even if you earned no income.

Since 2010, the American Opportunity Credit gives you a $1,000 even if you earned no income.
Wow! What would that be under? I did my taxes via turbotax n I did not come across a form like that.. So I qualify for 1000.n my hand during unemployment times?

Yes, as long as you were attending school, paying tuition and could claim yourself on the tax return.