Aha! Although ESET SysRescue (run from a newly created DVD) said that it has the latest virus definitions, in fact the definitions file was dated some months ago. After connecting the infected computer to the internet from SysRescue again, this time new virus definitions were downloaded and a scan then found and removed multiple threats.
I have now removed threats using ESET SysRescue, and a similar rescue DVD from one of ESET's competitors, as well as removing Windows Registry entries added by TorrentLocker.
Do I now need to run a repair from the Windows installation DVD, completely reinstall Windows, or something else?