i don't mean ping the phone. if you know the ip address of the phone and its working ok, then you get the dhcp conflict error, unplug that phone, and ping the ip address it had. you shouldn't get a response since you unplugged the phone. if you do get a response, the address is assigned to something else on the network. make sure none of the components of the G700/S8300 have an ip address that is in the range of your ip phones.
An example of overlapping scopes would be this:
ip phone range =192.168.100.10-192.168.100.50 (all ip phones would be assigned an address somewhere in this range from the DHCP server)
laptop ip address range = 192.168.100.40-192.168.100.100
that's an overlap of 10 ip addresses.