Thought I'd post an update now.
I installed everything in the new motherboard, on the motherboard box, on my desk.
Test run outside an case, before putting everything in, to make sure it works.
Pressed the power button on the motherboard itself and everything lit up nicely.
So it seems it was the motherboard that died then... Fingers crossed most stuff is still on my M.2 SSD though, so I can hopefully back that up before installing my new Windows 10 Professional
Thanks for the help though guys, especially to Excalabur50 and a huge one to SPS, for being on at the time and helping me out. Highly thankful and appreciated guys!