I have built a new computer last night and I have not gotten Cubase 8 to launch. I tried first installing normally with the updates enabled. Then I tried reinstalling over its self, then I tried uninstalling Cubase 8 and reinstalling with updates disabled during install. I have uninstalled it again and I am waiting on the download from MySteinberg to install fresh from Steiny. I have Cubase 7 32 bit installed and it runs. I also have 7.5 64 bit installed and it runs.
All I can think of is that it must be missing fuel, spark, or air.