Determining Whether a Windows Installation was Mass-Deployed

Windows OEMs use the Windows Automated Installation Kit and Windows Deployment Services to mass-image computers before shipping. If you're curious as to whether a computer you're using was set up in such a way, you can check for the presence of a file that indicates Sysprep was run. This file is at:

C:\Windows\System32\Sysprep\Sysprep_succeeded.tag

It's a zero-byte file that is created after a successful run of Sysprep, the generalization tool run to freeze a computer before using ImageX (or a WDS capture boot image). If you're curious as to the date of imaging, it's in the action log:

C:\Windows\System32\Sysprep\Panther\setupact.log