A little IT tip for you PC users. If your version of Windows (98, NT, 2000 or XP) has got a service pack on it you need to reload the service pack after you install or upgrade a major piece of software. Quite often software installs downgrade system DLL's etc. so re applying the service pack brings it back to Satan's, sorry, Microsoft/Bill Gates recommended versions. Might help with the blue screens. It's a pain in the ass having to do it, and not something Microsoft advertise very well, but I've found it helps sometimes.
I haven't used Cubase for a while but I remember Steinberg used to always release patches and updates fairly regularly after any major upgrade to their software. For some reason (shoddy programming, badly tested) they never seem to get the release right first time so check their website for updates and patches.