I hope someone else can benefit from this experience which I have now solved:
I had a burning smell from my PC which it transpired was a dud CPU fan. I replace the CPU fan with an upgrade - a water cooled unit from Coolermaster which is a monster of a unit and fiddly but straightforward to retro-fit. Whilst the PC was open I decided to get the vacuum cleaner in there and also add 16 Gb of ram 2x8 to the existing 16. I bought the same make but NOT I know realise - exactly the same as it transpired and 5 years on (the PC originally built 2015) this became an issue, because there was boot-up and hanging problems which only went away once he RAM was removed. Apparently additional RAM must be identical in all its original forms to be accepted alongside the old stuff. Certainly had me scratching my head I can tell you.
I had a burning smell from my PC which it transpired was a dud CPU fan. I replace the CPU fan with an upgrade - a water cooled unit from Coolermaster which is a monster of a unit and fiddly but straightforward to retro-fit. Whilst the PC was open I decided to get the vacuum cleaner in there and also add 16 Gb of ram 2x8 to the existing 16. I bought the same make but NOT I know realise - exactly the same as it transpired and 5 years on (the PC originally built 2015) this became an issue, because there was boot-up and hanging problems which only went away once he RAM was removed. Apparently additional RAM must be identical in all its original forms to be accepted alongside the old stuff. Certainly had me scratching my head I can tell you.
