Recently they released GNUradio for Windows. It sounded too good to be true, but apparently it's for real. It needs Windows 7 and up, and is x64-only. I downloaded it and tried it out this morning and was able to decode ATSC with it.
My favorite part of using Windows, apart from not having to wait for Linux to boot, is that you can record to a RAM drive and then select that file in GNUradio without having to copy it to the hard drive (of course, you should stop the recorder first!) The only catch is that you must use double slashes on your output TS filename in GNUradio, or the flowgraph will fail under Windows.
Once they finish CUDA support for VOLK, we can use live IQ from the SDRplay and watch TV as it's decoded.
You might want to see the Documentation, since it tells you little helpful things like clicking the GNUradio shortcut in the start menu; double-clicking .py files will not work.