Create a REG_DWORD value of 'NoPopupsOnBoot' in the key below (if it doesn't already exist). Set the value to '1' to disable pop-up messages from appearing. 

Key:[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Windows]
Value Name: NoPopupsOnBoot
Data Type: REG_DWORD
Data:(1 = disable messages)

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