finally rescued an old T61 that I was using as a Windows box. The application my bike's fuel controller uses needs Windows. I don't foresee needing that anymore so I swapped the drive with the original Slackware install. It's working very nicely now.
Windows was becoming to all intents unusable due to the I/O thrashing (an almost constant disk queue).
This is something that never fails to amaze me about Windows, and it's been a thing since Vista and they *still* won't sort it.