Anyhow, it's time to bin it now. I don't have extreme computing needs and find that an Intel i5 core processor with 8GB of RAM will deal with anything I throw at it, so I've gone for a used Thinkcentre. Obviously these are built as stable but boring office computers, but I am sure it'll be a significant improvement on the piece of junk I had previously. Stable is good!!!
Now I've got the task of setting up the stack of software that is involved in music/video/fractal/photo editing. It'll take a few sessions, no doubt!!