"aim high and to the right". The possible answers are in boxes that extend to the right about half way across the screen. Four boxes stacked one on top of each other. You don't see the boundaries but the boxes are there. You don't have to hit the little circle (exception: in the Brain twist that aren't FITB, you need to hit the circle (radio button). You can click to the right side of the answer you want to select. At least that's how my quizzes play.
Where do you get 8,000 points in a GC round? Starred topics earn 100 points each if you score above 500 on the quiz. But the 500 aren't points. They're a score level out of 1,500 max per quiz. Or is that a Hard Core tabulation? 65, legally blind on a ssllooww dial-up network connection. (I did just buy a new TV to use as a monitor to help me see the screens.) If you are using a Windows older than 8.1, an update will help. The clicking on an answer and not having 'it take' indicates you may be due for a new mouse.
I'm not belittling your problems but am trying to help.
The pointer needn't be in an exact position;
Old versions of Windows have communication problems with new site data arrangements;
Mouse clickers are one of the first things to go on them (unless you have a scroll wheel, then they go bad first).
Cats on keyboards cause troubles too.