VBox 4.3.18 is out. We'll close this thread and create a 4.3.18 specific one for tracking remaining problems. ( https://forums.virtualbox.org/viewtopic.php?f=6&t=64111
Just for the record, there were a few fixes after test build #10. Would be nice if @rnewman and @RelakS would give it a spin as I've made some changes to the hang/reboot/BSOD kludge.
@Mucky: Great that it works for you now.
@numb3rs666: Glad to hear it works for you too.
@eb: Good to hear that it's not vbox.
@frg: ATI+XP works, that's good. Sorry to hear there are more issues (though forgive me if I'm happy they're not security related and I don't have to fix them).
@Jacob Klein: Thanks for testing!
@just_to_report_a_bug: Some of the Comodo products (I don't know which exactly you're runnig) wants to sandbox things or modify files on the fly. Most Sandboxing solutions aren't good enough to contain VBox, so don't let it do that. Modifying files on the fly while we read them makes it impossible to verify digital signatures, since these depends on the file being unmodified. Please check the Defense+Events log in Combo (tasks -> general tasks -> view logs) to see what it's doing and what you need to tweak.
Knut St. Osmundsen