Why the hotkeys d’ont work anymore after switching to win7 with parallels?

Nothing is guaranteed with emulators, they can change behaviour at any time.

Sometimes emulators have different modes (like Windowed mode or Full Screen or Coherency or whatever they call it), and the different modes may behave differently.

Also, Hot Keys tend not to be honoured by the system if you are in full screen mode.

Actually I'm surprised that KM would work at all in Parallels Win7 since KM is a Mac app, not a Windows app.