My route was Win 7 Ultimate, Win 8, Win8.1 Preview, back to Win 8, then 8.1 via the Apps Store.
After MUCH effort and help mainly from this forum, it is at last working correctly.
Intel Dual CPU 2.6, 32 bit, 4GB memory home built with a mouse.
What may be important to some of you is that I have managed to get all of my old applications working correctly eg Nero10 which is meant to be unsupported on 8.1
File History works!, together with an automated system image backup to a 2nd hard drive.
Thus Win 8.1 is now a great operating system on this 3 year old computer!