Non standard image computers

[james_mitchell]

SUBSTRING(dbo.tblOperatingsystem.SerialNumber, 1, 9) <> '55274-640' AND
dbo.tblComputersystem.Domainrole = '1'

I dont get it?

[Hemoco]

It's an example to check if some computers have the same serial number (to see if they are cloned/imaged from a single master)