I am sick of not being able to run and install certain applications on my work computer due to admin restrictions (eg: Adobe AIR) . I have heard of smaller versions of Windows running on a usb thumb drive and have looked into it but can't find anything on running windows virtually from a usb drive.

I would like to be able to login to this particular computer, insert my usb drive and then open up another version of windows installed on the thumb drive while still being able to use the windows I logged in on (literally be able to alt+tab between the main desktop and the virtual desktop from the usb drive).

Is this even possible? For further clarification: The version of windows has to be Windows XP and there is no other option available for what I want to do.

Looking forward to a response.