The question has arisen around Volume License installations of Live Communication Server (LCS) sometimes prompting for a CD/Product key during setup. The Volume License media for Live Communication Server (LCS) will not prompt for a CD/Product key on a clean installation. However, if you are trying to upgrade a previously existing retail version of LCS, or a 120-day trial version of LCS, or an MSDN version of LCS it might prompt for a CD/Product key during setup.
The work-around for this issue (if upgrading from a previous retail version or MSDN version) is to uninstall the previous version of software first, and then install LCS using the Volume License media.
If you are upgrading from the 120-day trial version you can download a file to help upgrade a trial of LCS to the full version. That download is located