.V01, .V02 files

It sounds like your USB drive is formatted FAT32, so that maximum file size
is 4GB, the .V01 and .V02 (and V03 ...) are just extensions of your VHD file
due to the maximum file size allowed by FAT32. You need to keep all of
them...

the .vsv's are from saved state sessions. (you closed a VPC session saving
the state, rather than shutting down the OS.) These would go away if you
just restored the session and then did a normal OS shutdown and the close
without saving state.