CPU overload before project even plays, Cubase crashes

Cubase 9 got stuck when booting.
I did a hard reset on my pc
since then Cubase 9 starts normally, but has serious problems

when playing even the tiniest project [1 audiotrack]

1 there is no audio what so ever
2 CPU / RAM metering goes up to 100%, without the project even playing back
3 when shutting down cubase 9 the application crashes
4after crash Cubase 9 wont boot anymore

I reinstalled Cubase 9 twice with the latest update, no success,

I reïnstalled my audio drivers, no success

How do I get everything back in working order?

Hi,

Could you try a Safe Start Mode or trash Cubase Preferences, please?

Could you share the crash dump (Documents/Steinberg/crashdumps)?

You have plugins inserted on that audio track? Does the problem persist when they are removed? Does this happen on a new project or just this one?

I have seen plugins cause this behaviour on more than one occasion