In some cases a software author will decide to make his/her program available to the public at no charge. This is usually termed "freeware" and although free is still protected by copyright. It cannot be duplicated, redistributed, or modified, for anything other than personal use, without permission.
Computer software can be protected by both copyright law (as a literary work) and, when applicable, by patent law. In many cases, the End User Licensing Agreement carries more restrictions than copyright law would require; thus it can be viewed as contract law as well.
In IT, copyright most often applies to software, which can be protected by both copyright AND patent law. Most software-related copyright issues are addressed in detail in end user licensing agreements.
Public domain software is generally made available at no cost.
The End User Licensing Agreement specifies how copyright law applies to a program.
That would be considered "open source" software.
Copyright infringement in general is copying, altering, or distributing protected material without the permission of the copyright holder. If you have a software license to put a program on one computer and you put it on two, you have infringed the copyright. More details can be found in the End User Licensing Agreement (EULA) of the program.
To purchase licensing rights for software, you typically need to contact the software company or developer directly. They will provide you with information on the available licensing options and pricing. Once you have selected the appropriate license for your needs, you can proceed with the purchase by signing a licensing agreement and making the necessary payment.
Limewire holds copyright on its software, trademarks on its name, and more. However, they are not the rightsholder of the files made available.
Freeware or Shareware, like any other software, is copyrighted. The creator or author has released the copyright to the public and there is usually a statement somewhere in the documentation to that effect, as well as any possible restrictions. Restrictions may be that the Software can be freely shared, but cannot be sold, or incorporated into another software package. They also usually require that the copyright notice be included when sharing the item.
The Apple Education Licensing Program for schools and institutions of any kind provides software updates for their software products. License upgrades are available yearly and guarantee new releases.
Copyright treats software as a "literary work," meaning that just as a book, only the rightsholder can copy, alter, distribute, or display it, or authorize others to do so. Notably, the End User Licensing Agreement often gives the user more leeway.