Even worse: immediately after launching CB7A, the Windows Task Manager showed that the Program doesn’t respond anymore. Thus, I eventually thought, an upgrade to Cubase 7 Artist (CB7A) would resolve the problem.
Investigation on the Internet wasn’t getting me anywhere. Some days it never worked, on rare days it started CB5E like normal. The start graphic appeared, the initialisation of components began, but at ‘Initialising: MIDI’ the launch program often (not always) froze. Afterwards it always took several attempts to get CB5E started. On WinXP Cubase 5 Essentials (CB5E) used to work fine. Perhaps this could become valuable fo others, thus I am describing it in a bit more detail here: Today I was succesfull to resolve the above briefly described issue - by repairing the Windows 7 using the Installation CD.