I want set up a virtual machine on a thumb drive and load it down with tools for repairing borked Windows installations. I figure i need just enough to piggy-back on the machine's installed drivers 'till i can download new ones. So first, I need to decide which VM software to use. Anything that'll get the job done, no bells and/or whistles needed.
Wouldn't a bootable Linux "live CD" (such as Knoppix, Ubuntu), or a BartPE disc be a better solution? If the system is "borked", surely it's going to struggle to run any VM software..
It also means you can access/edit/delete files that would otherwise be locked
QEMU for Windows or QEMU is very portable, but slow. Should be fine for a no-frills machine. After that, Damn Small Linux is quite good, or do a custom Gentoo install (is there any other kind? :D).
There are a few to choose from in this little project - UNetbootin.