http://www.supportnow.biz/flash-usa/

Do customs check laptops for authenticity of software at USA airports?
or other media like CDR’s or DVDRs, Flash drives and external hard drives? Thanks!
Not as far as I know. I’ve travelled with laptop, CDs and USB pens before many times and never even been asked about software. I think they are more concerned with checking that there is nothing hidden in the computer (knife, gun, bomb etc.) than if you have a copied version of Windows…
…not that you should have a copied version though!