Thanks Eddy, I’ll check out that application.

I run memtest86 overnight but I’m not sure I chose the right option. I set it at ‘default’ and after 12 hours it was still running! At that point I aborted as there were no errors reported that I could see, but I wonder whether I should have let it conclude. How many hours does it normally take?

Anyway, I think I’ll try reinstalling Windows today and see if that helps.