The easiest way to create a dummy computer account is to simply use the Active Directory Users and Computers (ADUC) MMC to create it.
- Launch ADUC from someplace where it’ installed. (either on a DC or someplace you’ve run the AdminPak.msi)
- Navigate to the OU/Container where you’d like the object to reside.
- Right Click on the OU/container and select New->Computer
- You’ll be asked to specify the computername.
- That’s all there is to it. Now you can add the account to AD groups like a real active computer account.