I've read a lot of those and frankly none of them helped.
The first thing to realise is that SysTweak re-installs itself if you remove it from the directories.
I used HitManPro, an excellent tool, to remove it. However, within five minutes of logging back on it was displaying itself again. So the question was "How did it reinstall itself?".
After using HitManPro again, before I re-booted, I searched the file directories and found nothing. So I started to think about other places references could be. The answer, of course, is in the registry. Using regedit run from a command line, I searched the registry for every reference to SysTweak. On finding a reference, I deleted the containing "folder". After I had finished that, I re-booted.
SysTweak has now disappeared from my system.