MagicMike
Advice? If I disconnect my PC from the internet, can I create a very basic virtual PC machine that resides on my PC and use that to connect to the internet? Does my internet adaptor have to be enabled on the host PC?
You can install a virtual Linux system within Windows, and go online with that. It's free. And it would be Sandboxed, so that Windows will stay offline and untouched.
You can still go online with Windows if need be for short periods of time, to authorize for example. You might also have to download with Windows, since Linux downloads files as "tarballs," which won't open in Windows. But, you can be religious about your downloads, and not install them until you have scanned them, with Malwarebytes for example. Or even MSE. Or doenload on another Windows computer, scan for malware, then save to an external drive and install from there.