Need game ideas for semi-crappy system

So, while I don't have money right now to make a computer of my own, I do have a Dell Studio 1555, with intel penteum inside. And I'm wondering if anyone has sugestions for decent games that would work on a web brawser level PC (Windows 7). I like indie, fps, and games that really make you think. And nothing againts old games, but I'm  more interested in newish games.

Always advisable to check Steam. Plenty of indie games, some are free to play