Do I need to build a "gaming" computer?

[Justaguy]

I find that a lot of problems with older games on newer PCs and newer operating systems is that they simply aren't compatible unless they've been updated by sellers like Steam (thank god for Steam). I'm not a massive PC player either, I usually use it to play games that I can't get on console (Total War).

If you need sites that give specs for different games try Steam, they have a wide selection of games, new and old. Failing that you could try GoG.com which has a few games that Steam doesn't. I don't think you really need a high end PC for the games you're talking about, you could easily buy a cheap pre-built gaming PC, just be sure to get one that matches the specs you need.