Flash Drive Webserver

Here are some links to webserver+PHP software designed to run from a flash memory device.

XAMPP Portable

 https://www.apachefriends.org/index.html
 http://portableapps.com/apps/development/xampp

USBWebserver (last updated in 2013)

 http://www.usbwebserver.net/en/

Portable Windows Demo (experimental)

 DesktopWebserver#windows_desktop_cms_demo

Keep in mind that portable apps don't need to be installed on a removable device. You can also run portable software from a local hard drive. Portable software is low-impact nature and can be easy to maintain.