As I was running through the scope wizard in DHCP for Windows Server 2008 R2, the wording on the wizard was slightly confusing: it seems to imply that changes I make to the default gateway and DNS servers for this new scope will be applied for ALL scopes. That doesn't really make sense, but I wanted to ask to be sure: can the new scope wizard mess up other scopes or global DHCP settings?
In short, no. The only thing that will mess up existing scopes is if you run the wizard and create scopes that overlap. Other than that, each scope is treated independent of each other. You can check out this blog post for a little more info.