help replacing computer on a network

What do you mean by "run the network off the new computer"? Is this new computer going to be the server? And if so what roles does it need to do? What operating system did the old computer run?

Also if this is going into a business I would recommend you return the Acer as it's not a business class computer and buy a quality system, you may want to buy a proper server or at least a business class workstation with RAID capability.