Is it possible to use Virtualbox to boot from that old real drive instead of from an image?
Yes. VirtualBox has support for using a raw host hard disk from a guest since version 1.4. As of version 2.2.0, it is still listed as an experimental feature. It is described in section 9.10 of the user manual for VirtualBox 2.2.0.
There are some instructions for running a WindowsXP guest using a raw host hard disk on a linux host:
- http://mesbalivernes.blogspot.com/2008/01/virtual-box-booting-from-existing.html
- http://ubuntuforums.org/showthread.php?t=769883
If so, what are the implications for drivers, etc, since the “new” running OS will be using VirtualBox’s virtual hardware and not the original hardware on which XP thinks it was installed.
The second link above describes some steps to prepare your XP system prior to booting under VirtualBox.