Three of four computers can connect to the internet.?

I can't seem to resolve this issue. A cable modem is feeding into a DLink DI-614+. That is sent to two computers and a printer. These all get IP's and can share files, print etc. The fourth output is sent to a simple 4 way Hub's WAN/Uplink port. The hub then connects to two additional computers in an office located less than 100' feet from the router. The third computer receives an IP and can connect without issue. The fourth computer shows it is connected to the network, however receives no IP address or Internet. The settings seem to correct, they are the same on all computers, other than IP's obviously. These computers connect on their own fine. Additionally, when I plug a switch in before the router and hub, the router works and all computers on this router connect, but no computers work on the hub. Am I missing something? Is the simple hub acting perhaps, as a switch therefore not sending an IP to the fourth computer? I've looked for documentation for the hub online with no avail

Three of four computers can connect to the internet.?auto protect

I suspect your simple 4 way Hub is actually a router, since you describe connecting the WAN/Uplink port.

Another possibility is this is an exceptionally cheap hub that has five ports, but only four can be used.

I had previous experience with a similar cheap piece of s**t. In this case, the WAN/Uplink port (let's say port 1) is actually wired in common with the adjacent port (call it port 2). If you are connecting to another switch/hub, use the WAN/Uplink port and skip port 2. If you are setting up a standalone workgroup like a LAN party, skip port 1 and use the other four ports to the right. So in one configuration you can use ports 1,3,4,5. In the second configuration you can use ports 2,3,4,5. If you have ports 1 and 2 both connected to live devices, connectivity goes to hell if when devices on ports 1 and 2 go active at the same time.