I just installed VirtualBox 4.0.0 on Ubuntu 10.10 AMD 64-bit host. However, I can not get past the following problem:
Windows failed to start. Status: 0xc0000225
I solved this same problem by modifying these VM settings:
changed chipset from PIIX3 to ICH9
enabled IO APIC
enabled absolute pointing device (although this is probably not important)
from: https://forums.virtualbox.org/viewtopic.php?f=2&t=37628