Group Policy Preferences targeted at the computer would be the most "user friendly" way to make this change.
Assuming that all these computers are in the same Organizational Unit (OU) in your Directory, created a Group Policy Object (GPO) at that OU. In that GPO, under the "Computer Settings", "Preferences", "Windows Settings", and "Registry", create an entry that targets the key and value you'd like to set.
Microsoft has step-by-step directions here but, honestly, the interface is intuitive enough that you should be able to figure it out. If you're concerned about testing it create a "bogus" entry first on an OU with a single computer in it and observe the results using REGEDIT.