Q: I'm trying to install a System Center 2012 Release Candidate product, but it’s asking for a product key that I don't have; what do I do?

A: As with the final versions of System Center 2012, a product key is required for a full installation of the release candidates. (See screen shot below.)

However, you can also access a trial mode by just skipping the product key entry, which will give you an evaluation copy for 180 days. This should be fine for the release candidates of System Center until the Release To Manufacturing versions are available.