My main desktop has slowly been dying over the last few years, so weird issue with the motherboard or the CPU that acts like bad slots for the PCIe and RAM too, mainly ram.
No errors or anything, just nothing happens when you start the PC, lights on, nobody home kind of thing.
What sets this off is if the mains is switched off. Once you get the PC to start, it works flawless as long as the power remains on at the wall, shutdown and start up work fine like this.
But my desktop is at the farm at mum's and I haven't bothered taking it home as we have moved 4 times in 4 years because the builder won't f**king finish the house, 4 years and still not done. So things have been in limbo for a while and I still have much of my stuff there.
My plan was to build a new PC... in 2017, but life got in the way in all areas so I can't afford to upgrade.
I finally had enough trying to start the PC by re-seating the ram and GPU while on, it's the only way it get it to start and usually takes about 10-20 attempts. Only worked when on for some reason.
So I ripped the board out yesterday and downgraded to my old high end gaming board and CPU from 2008-10 and it fired right away, actually still have that for sale on ebay as retro hardware

Now the issue is win 7 BSOD right away as the CPU architecture it totally different, AMD FX back to a more conventional design of the Phenom II.
I normally just run the win 7 install DVD and repair windows but I get an error saying that the version is different and can't be repaired. Not sure why, I never updated win 7 from that DVD other than a few of the critical CPU vulnerabilities from recent years and that malware that was infecting all kinds of industrial equipment, can't recall the name of it now. I never had windows updates turned on, so I don't know why it's complaining about an incomparable version, so it could only be from those patches.
I could do a fresh reinstall but I have not been able to backup all my stuff as the PC was playing up too much to be able to reliably do that without potentially bricking everything. I don't have a 2nd PC to be able to plug the drives in to back them up either, everything else is a laptop too new to have SATA or anything helpful.
I looked for a win 7 media creation tool, I swear I even had one on this very PC, but the internet insists one never existed.
But I know I made one or had the stuff to do one for a Ryzen build that never eventuated on a USB stick, but now being so long I am sure I have reused that stick elsewhere.
I reckon a current win 7 version on USB should work for the repair, but I haven't been able to find one.
One of you IT gurus might know more than I do?
Appreciate any help.