Older PC games that use the SafeDisc and SecuRom digital rights management (DRM) systems won't work on Windows 10, Microsoft marketing manager Boris Schneider has told website RocketBeans.tv. The problem mostly affects PC games delivered on CD-ROMs between 2003 and 2008. A web portal, arstechnica.co.uk, mentioned as examples BioWare's 2007 game Mass Effect and 2K Games' Bio Shock, also sold from 2007.
Schneider says the problem is a concern about security due to the DRM employed by those older games. That means they won't work unless users employ a no-CD patch.
Depending on the game, some research on the publisher's website might help. Some titles allow the copyright protection to be removed with a patch. If you're uncomfortable taking that step, then it's best to stick with Windows 7.