Disk2Vhd
First get Disk2Vhd. This is a super small utility written by the guys from Sysinternals (so it must be good). Just run it, choose drive C: (OS) and save the file. It runs while your OS is running. Once done you will have a VHD of your hard drive.
Virtual Box
Now you can simply create the Machine in Virtual Box and add the drive as the primary and boot from it. If you have any issues with BSOD (Blue screen of death) such as 0x0000007B it could be because the SATA drivers are not compatible. What I found works for this is to add the drive as an IDE instead. In virtual box this is easy:VMWare
I found the same to apply for VMWare, however VMWare doesn't allow you to choose IDE when adding the existing VHD. For this just add a new hard disk and choose the IDE option:Now simply remove these disks, close VMWare and edit the
.vmx
file
You should now be able to boot from either and not worry about exporting all your settings.