To cut a long story short: I thought my old computer (or, at least, the hard drive) was nearing the end of its useful life, so after some research, I ended up with a new computer. As it happens, it seems that my old computer may not have been quite as close to its end as I feared, but I have decided to persevere with the new one anyway.
To put it bluntly, yuk! Windows 8 is designed for touch screen tablets. Although most of the familiar Windows features are still embedded in it, the reconfiguration of the Start arrangements makes Windows 8 less than optimal for a conventional computer. In particular, Windows 8 doesn't come with an option to allow you to use the previous Start menu. While it's not too hard to avoid the Start screen and work from a familiar desktop, sometimes you just have to go to the Start menu - for example, to turn your computer off! There you have to negotiate the strangely-named "Charms" to find (eventually) the "power off" button.
I am still working my way through these issues, and live in hope that a service pack may be issued that reinstates the possibility of opting for the traditional Start screen (rumours of this exist in cyber). Otherwise, I may be tempted to install one of the non-Microsoft patches that offer to do this, something that so far I have been reluctant to do in view of some negative comments that I have come across about these on the internet.