The company I work at goes through computers fairly regularly. When we get a new computer, someone has to manually go through and remove all the bloatware that comes with the computer. Right now, I am compiling a database of known bloatware and their silent uninstall commands, but many programs either don't have or require a silent uninstall script to be created. I'm wondering if there are any methods that I have missed that would silently reduce the windows installation to just the barebones OS and drivers.
SnapOverflow
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.