So I assume that your Windows 7 PC isn't connected directly to your TV and DAC/Amp/Receiver?
You want to run MC on a Windows 7 PC and cast the output directly to your TV, to both show Video and play Audio on the TV?
Do you have a smart TV that is capable of acting as a DLNA renderer?
Is your TV connected to your home network?
If so, you can just stream your MC content to your TV using DLNA. No need for a Chromecast device to do that.
If you don't have a smart TV, on the network, and capable of acting as a DLNA renderer, then you could buy a cheap Intel PC on a stick and send MC content to that. Okay, I'm not completely sure about that one, as you would need a DLNA renderer on the stick, or to be running MC on it, I would guess, and that may not work well.
But since you don't want to buy in to Android, and probably equally don't want to get an iDevice involved, DLNA is probably your best solution.
But there are so many connectivity solutions now. If you want to cast from Windows or a Windows Phone to your TV, then
Miracast is a possibility. You can buy a
Miracast dongle to use in a similar way to the Chromecast. Android can also use Miracast. Or if you use an iPhone, you can just Airplay to your PC running
Airserver.
But really, I am getting ahead of myself.
What are you actually trying to do, what is your PC, how is it connected to whatever it is connected to now, and what is it connected to, what content do you want to stream, just local files that MC knows about, or what???
Also, there have been a few posts about such setups. You may find what you want to know with a search. Just make sure before you do any buying that you check what resolutions, frames rates, video and audio formats, are supported, and what the hardware and software prerequisites are. Check carefully what your PC and TV are capable of.