I have spent the last 24hrs attempting to get my PC back up after a c**k-up beyond belief.
It started with me looking over a package that Des in beta.
I won't bore you with how it got from there to what I was actually trying to do but it did include Google Earth.
The upshot was that I found a tip for increasing the boot time on a PC by altering two parms in the mcsonfig tool in windows.
So I went in and sure enough the number of cpus that were set to be used on start up was set to 1 and there was no memory allocated. So I set them to 4 and max memory and rebooted.
... or so I thought.

All I got was a blue screen with an announcement that there was a bad_system_config_info.
Terrific so I needed to change it back, except that it wouldn't boot and you can't boot into safe made with Win 10 as the F8 key doesn't work any more, so no last good config available, and it turns out that 10 doesn't offer that anyway!

So 10 hours on the internet says that you seemingly can recover using F8 and safe mode for Win 7, but not for after that. Terrific. So I was in the position of trying to use the MS MediaCreationTool to create a boot iso and use the upgrade option and hope that reset the msconfig info.
I decide that I would ring MS Tech support before I did that, but first I created the iso on the PC that my missus uses.
MS tried but when I had to explain to them that you couldn't use F8 to boot for safe mode, I felt that this was not going to go well. I also had to explain that it didn't boot at all and there was no recovery option.
So I asked if upgrading to the Anniversay version would fix the registry issue but they wouldn't guarantee it and suggested a clean install. That might be fine for people who have about 6 programs on their PC and know where all the files and registration info is but for me with 154 programs on my C: drive and god knows how long it would take that would be a last resort.
Now for the Windows 10 stuff
By luck I actually got into a repair mode I tried to boot from the MediaCreationTool iso on my usb. It knew that the files for the anniversary update where already on my PC and asked if I wanted to continue or start for a clean install. At that moment I hadn't committed to a clean go so I powered off the PC removed the usb and powered back on.
It knew something was wrong and went into Windows 10 recovery mode and gave me the all the options.
Did I fix the boot problem?
Yes, one of the advanced options is to boot into the elevated command line. which i selected.
There is a Windows command which is used to modify your boot info and I should say stay clear unless you absolutely know what you are doing - even then reread the docs. The command is 'bcdedit'
When typed it lists the entries.
What you are looking for, if you have altered the msconfig boot data are numproc (number of processors) and truncatememory (max memory).
If one or both of them are there then the following commands will delete the entries.
bcdedit /deletevalue {default} numproc
bcdedit /deletevalue {default} truncatememory
N.B. yes the {default} is what you type not a variable.
Now bcdedit again will confirm that they are gone. You can now exit the recovery mode and reboot and you will now be rewarded with your Windows booting up as it should.
Google Earth???
Yep, en-route to my situation I had an issue with Google Earth. So I decided to uninstall/reinstall it. Mistake. It seems that Google have not updated it since Windows 10 came out and for quite a few people it will not install unless you clean out the registry, which smartly I decided against. You get and install Error 1603.
So I haven't got Google Earth installed any more and I will have to wait to see if the new update fixes it.
Should I not tinker with the boot options in msconfig then?
No you bl**dy shouldn't.
signed
A very, very relieved Bunny.
P.S. I have also emailed the fix to MS so hopefully somebody else will benefit from my tension.