Recent Vista 64bit Home Premium installation over the weekend. Have only installed one piece of game software Steam; downloaded HL2:LC, CS:S and DOD:S.
When I clicked on Game Explorer it has asked me if I wanted it to look for recently played games. I now have a HL2 icon which points towards CS:S, and doesn't work. The icon itself looks fine although it says 'no rating provided' under the icon.
Sorry, not sure if that helps, but my current experience.