Ok guys, first off thanks for responding. However, umm where to start, okay Brian, first come, first served.
"I cannot recall how Windows 7 licensing works as far as identifying the hardware associated with it."
To all intents and purposes, surely, this would only be relevent, if I was actually installing another OS?.
When you instal an OS, you are installing it onto a HDD and then you register it. But I'm not intending to do that. Because Win7 is already installed and registered on the HDD that I would be placing into the new PC. I can see where you're coming from though, you think that this might be some kind of ruse. That I'm trying to pull the wool over the eyes of the Microsoft registers. But what I'm actually trying to do is access all the programmes that I've installed down the years and used to use daily. Programmes, some of which I paid for and many more that were free at that time. Software, that I would be hard pushed to replace, if it were even possible. Some of the paid for ones were downloaded (no disk's). I have much ongoing work using these programmes, work that is non transferable.
I think that this (above) more than answers your question...
"Why would you want to even try to hang on to an OS that has less than 13 months of support time left?"
...Also, no disrespect, but if you had read or remembered what I said at the onset, you could have answered some of that question for yourself...
"...a second PC. So I could have one to go online with, send and receive emails and get updates. The other I'd use (offline) souly for my work..."
The old PC with Win7 would be the one I wouldn't go online with. Having both OS HDD's in the one PC and switching back and fourth between them. Would simply, (if you can use simply in this case?) be a short term workaround. Until I can raise enough money to get another PSU for the old PC. If the PSU does the trick, I can then replace the Win7 HDD boot drive back where it belongs.
"...I cannot see any advantage, none, to putting off the inevitable."
Any other place, any other time, I would relish debating with you. I truly believe that debates and heated arguments are the only things I really miss from my past life, if I really miss anything!.
As for Win10...
I generally move with the times, I've always looked to new horizons. I love progression, when it helps me and mine for the better. However, if I don't consider it's doing that, then you better believe, that I'll rile against it with all the fangs, claws and venom I can muster. But, let's face it, for someone like me to even verbally go up against an organisation like Microsoft, is like flogging a dead horse. Still, in answer to your question, for now, only death is inevitable.
"If your intention is to remain a Windows user..."
Yes it is, while I can continue to use the OS I want to. If or when that might cease to be an option, I can always step sideways and embrace a free OS. Although, many people are still using XP, why, because it suits them...Vive La Difference.
"...to reliably have a 'dual boot' system both operating systems need to be on the same physical drive, if you install Win7 on your C drive where W10 now resides it may overwrite the W10 boot manager..."
Again...no disrespect, but if you had read or remembered what I said at the onset, you would not have needed to make that uninformed statement.
"...Win7 64bit Pro HDD sata boot drive and swap the plugs from the Win10 64bit Home HDD sata drive."
IE Both OS HDD's in the same PC, at the same time. Swapping the MOBO plug and the POWER plug from Win7 HDD to Win10 HDD as and when each drive was needed.
"Since Win7 is an older OS, and as britechguy mentions will soon be unsupported, it would probably be good to get used to W10. The best thing is at least your work wasn't affected, those drives can be hooked up in the new computer easily."
I respect your/everybodies views, however, please read my response to BRITECHGUY (Brian)
Well, at least you have read and remembered what I said at the onset. Even if you have chosen not to respond to my full question. Still, I found the software...'Sysprep'...interesting. Although, I don't believe it's something I need or want.
As you say, I'll probably just do as I originally intended and get another PSU, for the other PC. However, it'll not be a lower wattage one than I already have or had, it'll be the same or better. People are telling me that the one that went bang was probably because it was under too much continuous strain. It was a Corsair 850W.
At least then if it doesn't boot I'll have a back up PSU for the new PC. Although, I don't know where it might stop. People seem to think that everything could be knocked out!. I don't want have to source the same ASUS SE MOBO, then maybe another i7 Quad Core CPU and who knows, another Arctic Extreme Cooling System. I might have to get another 'top of the range' Nvidia GPU and a new Creative Sound Blaster Z PCIe Gaming Sound Card with High Performance Headphone Amplifier and Beamforming Microphone. Plus another 32GB ram, Oh and it was all wrapped up in a Cooler Master Case. The new one can't hold a candle to the other one.