The Xbox 360 at release was 400$ (It's now 300$ for the 250GB version),it has nearly been around for almost 6 years and there has been literally no major hardware upgrades too it...I highly doubt you'll be able to find a PC that is 6 years old that did cost 400$ that will be able to run every game on PC (with medium/high settings).
My point was that you spend the same either buying a gaming PC, or a regular PC and console separately.
My rig was $800, including monitor.
$300 for console, $300 (at least) for a separate PC, $200+ for a TV (assuming it's an HDTV). That's $800 right there.
But no, not for $400, but I'm sure there are a few systems that were $600+ back then and will run Skyrim fine. Perhaps not EVERY PC game, but any game a 360/PS3 can run, a computer of the same specs can run. Regardless of when it was built.