Windows suddenly decided it doesn't want to play any more

[audio2u]

Hi all,
First time poster.
I have a home-built machine, based around an Asus Sabretooth motherboard, AMD FX8350 CPU, 16GB DDR2 RAM, dual booting Win7Pro/64 and Linux Mint.
I'm writing this post logged in to Linux.
'Cause... y'know... that just works.
I've been running this system with both OS's for over 18 months now. Generally, my Windows install has been super reliable.
Quick bit of background on WHY I run dual OS's.
I would happily move entirely to Linux... except, I'm a professional audio engineer, and the software I use daily will not work on Linux. Some of it will, but not all of it.
So I keep my Win7 rig spinning for audio and video work, and everything else happens on Linux.
Anyway, about an hour ago, I logged out of Linux, with the intention of booting into Windows to do some audio work.
Motherboard logo appeared during POST. Check.
GRUB menu appeared. Check. (For those not familiar, GRUB is a bootloader which intercepts the Windows bootloader and gives you the option of WHICH OS you want to boot into).
Selected Windows and hit Enter. Check.
"Starting Windows" message appeared. Check.
And that's when it all went sideways.
I got what appeared to be like a BSOD, except it didn't even get to fill the whole screen. It lasted for about 1/10 sec.
It started from the top of the screen, and filled maybe 10% of the display, before the entire screen went black, and before I knew it, I was looking at the motherboard logo again during the POST.
Next time around, I got the "Windows failed to start" error screen with the options to "Run repair" or "Start Windows normally".
Like any normal user, I tried "Start Windows normally".
Groundhog Day!
Next time around, I chose "Repair".
Got the "Windows is loading drivers" display for about 5 seconds, then suddenly, back to the "Windows failed to start" screen.
So I went round and round a couple of times on this, with a couple of reboots thrown in for good measure.
Eventually, I pulled out my Win7 install disc, and set the BIOS to boot from DVD-ROM first.
THAT got me to the GUI screen where I could choose to either "Repair Windows" or "Install Windows".
Naturally, I tried the "repair" option first.
That failed, and brought me back to a screen with a bunch of different options...
- Try to repair windows
- Run system restore
- Recover windows from a recovery image you created earlier (Nope, I don't have one)
And I can't remember what the last 2 were.
Basically, nothing here helped.
So, I reluctantly thought "Looks like I'll have to do an install", thinking that I would be able to simply install a new version of the OS but keep all my apps intact.
When I chose "Install", the next screen asked for "Upgrade" or "New install". The small print explained that an "upgrade" would keep all existing apps and settings, but that an "install" would lose everything. It also not-so-helpfully advised that I back everything up before proceeding. Yeah, thanks for that.
So I tried the "upgrade" option, but the installer immediately gave me a "This is a Win7 installation disc. Reboot, try again, do not pass go, do not collect $200".... or words to that effect.
Basically, I'm fretting now because there are apps and plugins which need to be deregistered if I'm going to do a clean install, but to deregister them, I have to be able to log in to Windows.
Sorry for the epic post.
Does anyone have any suggestions for things I haven't yet tried?
Thanks in advance.

 

[audio2u]

OK, I was about to pull the pin and install Win10 (which may or may not work with my soundcard... I'll find that out when I get there).
But I have one fear.
The current layout of the drive is....
sda1 is GRUB.
sda2 is the Microsoft bootloader
sda3 is where Windows lives, and
sda4 is my Linux install.
Question..
When I go to install a clean copy of Windows, should I delete sda2 and sda3, and then tell the Windows installer to use that unformatted space for the new install?
Or should I point it to the existing sda2 or sda3 partitions?
My worry about removing sda2 and sda3 is the notion of having unformatted data in the middle of the disk, while there are active partitions at the head and tail of the disk. Is that an issue? Will Windows be smart enough to take the unformatted space in the middle of the drive and successfully create new sda2 and sda3 partitions?