I able to succesfully move linux installed on VirtualBox from virtual hard drive to physical usb drive.
I use unix dd command to read whole virtial harddrive and use physical usb flashdisk as output for dd command. It works perfectly with linux. And I can boot computers from flashdrive to OS I was using on virtualbox.
I would like to do the same with Windows XP SP3 or maybe with Windows 7 if it won't be possible with windows XP.
I get bluescreen in Windows XP SP 3, czech language mutation during the boot. And I see only blank black screen in english language mutation of Windows XP.
I would guess that the problam can be that I installed windows on IDE controller with type PIIX4 but booting from usb uses different controler.
Other options are PIIX3 and ICH6. I could also try SATA, SCSI, SAS or floppy controlers. Would some of these options help me? Or am I missing something?