Automated Installation of software and MS windows

I have a lot of computers that i install windows 7 and Windows 8. Then on top of it i install my own applications that are required to work with my product. There is a lot of configuration that goes into this installation and each installation takes me around 4 to 5 hours. Plus over night testing. I am looking for someone to provide me with an Automated solution for this installations. Also if anyone can recommend if an Appliance Edition would be a better option and how to get that version? I want a solution where i can have all my software, configuration and windows software and any scripts to run from a USB stick. Also if anyone can recommend if creating a image of a pc will be better, but the problem is my hardware keeps changing so there will be issues with drivers.