After some problems I got VirtualBox 4.3.2 installed on my Windows 8.1 Enterprise, but it doesn't work at all! I tried several versions of Windows XP Pro and Windows 7 to install virtually with VB, but all what I got were BSODs within the guest-OS! Could Avast! Antivirus Free 2014.9.0.2007 have something to do with the no-go of VB on Win8.1 Ent.?