Using qemu and vmplayer, I created a vmdk file (and corresponding vmx) that had a complete windows installation on it. Now I am trying to switch over to virtualbox, but the machine I created using said vmdk file fails to boot. While booting in safe mode, it hung up on agp440.sys. I found this page: http://www.virtualbox.org/wiki/Migrate_Windows and went in to the system files and renamed it agp440.sys.backup. Now it hangs on Mup.sys during boot. Just to experiment, I also renamed mup.sys to mup.sys.backup, but then it hung on NDIS.sys. Not sure what is causing this as it ran fine in VMPlayer and Vmware Server.