Hi,
I have had issues installing Vista using a bootable USB due to the way the installer detects which drive is the primary drive. This was the error I had:
https://support.microsoft.com/en-us...ume-which-meets-its-criteria-for-installation
Normally I recommend Rufus for creating bootable USBs from an ISO:
Rufus - Create bootable USB drives the easy way. Works very well normally. You may have success installing Vista with it, it depends mainly on how the BIOS treats USB drives.
Personally, I ended up using a PxE boot server on my network to install it, but that's beyond the scope for this post I feel! Was far too much work!
-Stephen