Well I have learned an immense amount in two days! I must say that here in the UK, having read a multitude of computer magazines about upgrading to Windows 10, I have never once seen the suggestion that one must make a subsequent clean install to make it work properly. Definitely I have never seen any Microsoft info on this. I appreciated the need to upgrade to ensure the windows key is registered into W10 but did not realise the next steps. If this had been made clear (or I had researched it) I would probably never have started but now I am here I will press on.
In practice I suspect most non-literate users will stick with what they have, after all many still use XP. My final annoying postscript is an Australian friend who only really know how to switch his laptop on told me two weeks ago that he has Windows 10 now but does not quite know how he got it and it seems to work...............must be the Ozzie sun!
Thanks to everyone for their help and wise counsel.
It is rather unfortunate it's left out that due to the previous iterations system critical drivers being copied over, it's recommended to clean install... or something to that effect.
The issue isn't Windows 10, as Windows 10 will function perfect when upgraded from Windows 7 or 8, and you can demonstrate this by installing Windows 7 or 8 in a VM and then upgrading the VM to Windows 10, as VM's don't require drivers to function in the fashion most users are familiar with. The problem arises from drivers, as all of the previous Windows version's drivers are copied over to the new windows directory. To simplify this, when an upgrade is performed it's around 75% new OS, 25% old OS. If you bring up my profile and click on my previous posts, scroll back to some of the first posts I made after I registered, as many explain this.
Almost all who've had issues are under the impression it's because of Windows 10 and they often state they never had this problem on Windows X. Essentially, drivers are programs that allow hardware to communicate with the OS... in other words, they're critical to the user experience. Without drivers, you not only wouldn't be able to interact with the OS, you wouldn't be able to see the OS. Windows 7/8 system critical drivers [drivers for anything attached to the motherboard] are not compatible with Windows 10 and when Windows 10 is forced to run with them installed, instability and wonkiness follows.
For any user to take the stance they should remain on a prior OS iteration has either been massively misinformed, or has not taken the time to fact check what they've been told. Again, Windows 10 is not the problem... users' failures to educate themselves on the proper way to install Windows are. I pity anyone still running XP as I will guarantee if one is, and they don't have a corporate contract, they've been hacked and any personal information and photos have been siphoned. Windows XP is insecure and has been since April 2014. Windows updates don't just fix bugs and exploitable code... they point a big red arrow at how to exploit a PC running any Windows version that hasn't applied the patch yet.