While reading blog comments about Welcome Center, I came across this entry on how to remove welcome center at first boot.
With a simple .reg file though, you can kill Windows Welcome Center dead on first boot — simply put the following into your .reg file and save it, run it, or add it to your scripts:
That will do it. But if you run this command instead, you can avoid creating a file and the elevation prompt.
reg delete HKCU\Software\Microsoft\Windows\CurrentVersion\Run /v WindowsWelcomeCenter /f
Oh, and sorry about waiting until the second time you see it before displaying the checkbox - that wasn't my idea. (Welcome Center was a feature with a lot of input.)