Copyright law in US generally allows consumers to lease, lend, or resale legal copies of copyrighted materials they own. This seems to be common sense because it won't surprise anybody that a copyrighted book can be resold on ebay without any legal hassles. Such allowance is known as the first sale doctrine, codified in section 107 of title 17, the copyright act.
However, when comes to software, it is a whole different story. If you think you own your software purchased at bestbuy, you are wrong. Almost all the software makers have this term in the EULA (end user license agreement)
"The software is licensed, not sold. This agreement only gives you some rights to use the software."
Would you still shell out 100 bucks for the software program you bought, if you knew you only got a lease in return? Software's EULA usually comes with very stringent terms that defy some common protections afforded by the law, such as first sale doctrine, reverse engineering, forum selection, and etc. While some courts were fed up by software makers practices in turning every products of theirs into leases and thus invalidate EULA with respect to the terms of lease when disputes arise, still many courts will enforce such terms in favor of software makers.
But how many of us really know or even read these terms before we eagerly rip the shrink wrap off? And of course by opening the software, you automatically admitted this term
"BY USING THE SOFTWARE, YOU ACCEPT THESE TERMS. IF YOU DO NOT ACCEPT THEM, DO NOT USE THE SOFTWARE. INSTEAD, RETURN IT TO THE RETAILER FOR A REFUND OR CREDIT."