Have you checked to see if the dot is there during flight? It doesn't show when you are docked, even if the "show mouse widget" is set to on.
I feel your pain, I'm sure most of us have had to reinstall or reset Windows on several occasions, occupational hazard I guess. Recently I had to do a W10 reset and I found several game files including ED were still intact. So I deleted and resintalled just the launcher files. I'm not sure if it works for every situation but it did the trick and saved re-downloading the whole game.
I save my bindings file elswhere on the SSD and also on a USB stick. That way you can inject and replace the default file without the rebinding hassle if it all hits the fan.
It can usually be found in: Users/YourName/AppData/Local/Frontier Developments/Elite Dangerous/Options/Bindings and is called Custom.3.0.binds
Getting back to the dot, I've never been a fan of it's clunky design, there's been no change in it since Beta 5 years ago. I would much rather see a choice of reticle available, smaller with fewer pixels and different colours/designs similar to WOT etc. It's obviously way down on their list of QoL priorities but who knows, I nagged about a cockpit headlight indicator for 4 years and hey presto it turned up in 3.4!
