Most games will install the software they need when you install them. Otherwise the only real software you need to worry about is the drivers for your hardware. Mainly the graphics card driver which should for a true gaming machine either come from AMD (www.amd.com) or Nvidia (www.nvidia.com). Besides that most gamers will get their games from a service like Valve's Steam (www.steampowered.com) or Gog (www.gog.com) of which most of these services have their own client software. (Other services include ea's origin and ubisoft's unity, Blizzard's Battle.net, Desura, GamersGate, among a few others).