Silently uninstall bloatware

It's called a format. Just use a PXE server with some windows images. When a new computer comes in you automatically install a new windows image on it. In my experience, that's the easiest way.

Lucas's answer is the best way to go but if you have a situation where that's not practical you can create a machine image using an OEM install of Windows, customised to your liking. Give a copy of that image to your OEM supplier and instruct them to use it for all future PC purchases. If the supplier won't agree to do that find a supplier who will work with you.

PC Decrapifier is actually pretty good for this.