I have used a utility to "delete" them (Move It) and when I have done this in safe mode they appear to be deleted. But when I re-boot in normal mode they are there again with a most recent time stamp. Something is creating these files on boot-up in normal mode.
After much investigation I have discovered that Torpig creates/uses these files and I saw reference to this after using Spybot but I thought that it had got rid of it.