Sorry, I think my question wording is a little vague.

I've been trying to work through some Angular 2+ tutorials. At first everything was fine, then I decided to have a go at Angular-Material and/or Bootstrap 4 (which required updating to Angular 6). Upon attempting to get this stuff going, I ended up coming into problems where each successive step I took to fix things just made it all worse.

I'm now running into all kinds of errors, and can't even get a stock Angular project on Visual Studio (2017) to run. The errors started with things like 'Module Parse Error' and have now reached the stage where some parts of Angular don't even know they exist any more. I can't even use `ng new Project` to create a barebones project from the command line any more because `Unexpected end of JSON input while parsing near '...Ze433ne....'`

Honestly at this point I don't even care about working through error messages and/or finding a solution. I just want to reset the whole thing back to normal, as it was two days ago before I started all this.

For the sake of completeness, I guess I'll add that I've tried things like `ng update -all` and `npm cache verify`, and (what I believe is the main problem) I deleted a few folders from the npm-cache folder of AppData on my computer, as recommended by another response on here. I guess it would be good to undelete those folders, but if I attempt to restore them the process always stalls halfway through, so they're oddly stuck in the recycle bin.

As you can see, it's become a bit of a mess, hence the desire to just restart it all. 

Any pointers on getting Angular back to default would be much appreciated.

Thanks.