It surprised me to find that there are very few dead-simple guides to creating a bootable USB thumb drive for a Vista and/or Windows 7 installation. I cobbled together the following from VistaPCGuy and another source I don’t remember right now.
This will walk through the steps to create a bootable USB flash drive for the purpose of installing a Vista or Windows 7 OS. These instructions assume that you have a computer with Windows Vista installed on it.

Requirements:

• USB Flash Drive 4GB+
• Microsoft OS Disk Vista / Windows 7
• A computer running Vista / Windows 7

Read more: Kevin’s Blog