I'm not sure what could cause that to both games at once; neither has changed for quite some time. Was there a Windows or antivirus update perhaps, between the last time they worked and the first time this happened?
What antivirus app do you use?
CK2 is free to play on Steam now, does it have the same problem?
DXDIAG is a program you run from the Windows search box on the task bar. After running it will open a window and start collecting info with a progress bar in the lower-left corner. When it completes click the 'save all information' button and save it to a file then attach that file here.
Please attach here your Documents/Paradox Interactive/Hearts of Iron IV/pdx_settings.txt and settings.txt.
From your Documents/Paradox Interactive/Hearts of Iron IV/logs/ folder, attach here system.log , error.log .