>1. Using the system Performance rating (in Vista, W7 and W8) as a 'search argument' to see games that fit that profile -- alternatively using Steam to Benchmark your machine and then showing compatible game titles with various sorting options.
I was about to load up Steam to do this when I realised that you were talking about missing Steam features. Sigh.
If it helps, the machine can play Civ 5/Warlock: Master of the Arcane fine on low/medium.