QGC doesn't start up anymore

I was always using QGC on my Windows 10 laptop. Recently it stopped working. I didn’t do any changes on my system (except for a windows update) and also tried to run QGC in the GPU safe/compatibility modes, as well as an admin. I also completly wiped it from my system and did a reinstall. But nothing worked.
I always get a running QGC task in the background which then consumes ~30% of my CPU Power. But there’s no GUI nor is something shown in the task bar. When I try to open QGC again, without ending that task I get the “An other Instance of QGC is already running”-error.

Did anyone ever experience this issue?