Scroll bar on main menu scrolls straight to last item

When I click on the scroll bar of the main windows menu (bottom left button) and start to scroll down, the scrolling then continues automatically to the last item on the list so that I can't access the others. It is as if gravity has taken charge! There is no problem with scroll bars in web windows or in Excel. I think the same problem was happening in Word last week but it is not today. I have tried following various recommended fixes including a clean boot, running Windows defender scan and switching off some mouse functions. I am no computer expert so it is possible I have perforemd all these actions correctly. Nothing has solved the problem. I've also tried a different mouse.
Any suggestions as to what is the cause of the problem and how I might fix it would be very much appreciated. The graphics card is fairly ancient: could this be the problem?

Hi Dalchina,

Thanks for replying.
I am not doing very well with screen shots. The computer is now behaving worse with scrolling problems on web drop downs and QGIS programme not working at all well.

The scroll bar in the start screen is the one you indentified but as I say other scroll malfunctions are now occurring.

Mouse settings:
Roll mouse wheel to scroll = One screen at a time
How many lines to scroll at at time ( Slider set nearly to left end)
Scroll inactive windows = OFF

Mouse properties:
Vertical scrolling = One screen at a time
Horizontal scrolling = One character at a time
I fiddled around with these settings after I began to have problems. They were more like those in your screen shots intially. Anyway, they my changes did nothing to help the situation.

The problem is solved! It was a wireless mouse that was causing the problem and even though I'd disconnected the batteries from this, it seems that the dongle in the back of the computer was still causing problems. If it had a tail, I'd string it up by it.
Many thanks for your help. You headed me in the right direction.
Peter