And that, my friend, is why it always pays off to build your own PC. It takes some real skill, but it looks like you're OK with changing out hardware... wait, you did use those offsets, right? If so, then you're all set. It doesn't have to be top-of-the-line, but if you put together a machine it will last longer, run better, and be more satisfying than a pre-built machine.
I'm not saying that you have to put together a machine, or that it will be easy, but hey, if you can do it, and you do it, then you're all set.