ProTools crashing on startup

[Hazgrid]

Hi,
Really hoping someone will have a solution to this...

I've got a problem with Protools (2018.12). I open up Pro Tools, it starts loading the plugins/audio engine like normal, but then it closes... No error, nothing. I've gone through the normal troubleshooting steps, deleted the user preferences, deleting the plugins, reinstalling ProTools many times and still no luck.

I've installed it on a laptop, and it works fine. I've been using ProTools on my main computer for years now, but it's only now having an issue with it.

I've bought an ASC for the issue, called the support number; it says the code is invalid! Lodged a support case, they responded once, and I've not heard back since.

Thanks,
Harry