I don't have much experience in the matter but after reading some posts here:
Booting a Linux VHD
it seems impossible (for the moment).
You can only do that starting with Win7 beta and beyond. Vista is NOT supported and XP neither.
I got the answer some time ago at post #37 here:
Windows 8 VHD - Create at Boot to Dual Boot with
People do mention some work made by VMLite from here:
and eventually you go here (instructions): http://www.vmlite.com/appliances/ubuntu-910-readme.html
and there is something calledReal Applianceand that's what we're looking for. If you can set that up you can boot Ubuntu from VHD.
But that's still early and it's something I didn't got the chance to test.
One last thing (sorry for so many links) here is the page with sample VHD appliances (including ubuntu):
you can also try to make your own VHD following the instructions.
I am forcing myself to use Windows 8 right now.
I am working on something that requires Citrix, so I thought I would give Metro IE a chance. After all I might need to use Citrix on a tablet one day.
It kicked me out to the real desktop.
In fact I keep getting bounced around Metro and the real desktop.
Say, have you installed Windows 8 on a USB 3 flash device or something similar and ran it on a USB 2 port?
"The Start Screen is adaptable to the user, as it was designed to be. One must make it their own...."
If you are on keyboard and mouse. Keep one hand near the windows logo key. Use the windows key to get to the metro UI. Use windows+q to search and use windows+c to use the charms bar.
Ordering “Windows to Go”: how to create a bootable Windows 8 USB thumb drive | Ars Technica
Simplest instruction you can find. It applied to the Consumer Preview, but works just the same for the Release Preview. A suggestion though, look and the command prompt snippet for the commands, don't base it off what's typed in the article. I screwed up the btmgr part because of that and had to redo the whole thing.
I have Windows 8 To Go installed on a 16 gig, USB 2 flash drive. Before, I had the CP installed on it and lucky for you, I had Photoshop CS5 installed. It leaves about 8ish gigs left on the flash drive, which is enough for Photoshop (but select the 32 or 64 bit versions, don't install both) and I believe enough for Lightroom. Just a word though, it will literally take HOURS. USB 2 is the most slowed storage interface out there now, but it surprisingly works OK though. It takes about a little over an hour for Windows 8, and about another hour or so for Photoshop and probably will take a little under and hour for Lightroom. And when you install the programs, don't try to use the To Go drive, it won't get you anywhere as USB 2 flash memory is slow.