Most long-term laptop PC users know the tell-tale signs of a nearly full hard drive. After operating perfectly for years, suddenly your laptop starts to behave as though someone has poured treacle into its guts - or it freezes entirely.

If you are lucky/unlucky, every now and again a Windows message may pop up warning you that you are running short of disk space and inviting you to "cleanup" old files and remove at least some of the junk generated by everyday computing.