I have to admit that, while this idea is better, I went the other way. My production machine is hooked to the Internet and I do use it for other than music (like writing this). In years past, I kept it separate, but since Windows 7 I haven't felt the need. I also rarely tweak the operating system except for a few basic things like Power Scheme.

I have a laptop that I use for browsing the net. If that blows up from malware, nothing lost.

Peter Gannon recently posted that a Geekbench reading of 2000 or so should be sufficient for BIAB. I recall that 1500 used to be the guideline, so I conclude the BIAB needs for computer power have risen. Still, a machine I have that is five years old reaches over 2000 easily. The problem with Geekbench is that you have to already have the PC to run it; the sales literature can't tell you anything in advance.

One caveat about buying something from a retail store: the name brands like HP and Dell come with the minimum inside the case to support only what you bought. This can include a barely adequate power supply, no cables for added expansion cards, not even a place to put a second hard drive - things like that. So, don't count on being able to do future expansion. For this reason, I have built all my own machines since 1982.

Some specific answers to your questions:

I like a SSD as the boot drive, at least 256GB.

I like at least one regular hard drive for data, at least 500 GB. Western Digital Caviar Black (not green) is great.

I much prefer Intel CPUs. An I5 would be the minimum to do fine for BIAB now and the reasonable future.

I like the Focusrite Scarlett series of sound cards. They use USB. Get the one with the number of inputs and outputs you need.

And I'll just say, Windows 10 is really nice but you have the option of upgrading for free for awhile yet.

BIAB 2024 Win Audiophile. Software: Studio One 6.5 Pro, Swam horns, Acoustica-7, Notion 6; Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus Studio 192, Presonus Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors