My internet is running at max on all devices all except my desktop. I've recently had a cable guy to come out and check as to why formerly the internet was at 0.22mbps out of what's being paid for of 30 mbps. He replaced one thing he suspected that could be slowing down the internet and does another speed test on my desktop, still the internet is low but increased to 5 out of 30 mbps. He then goes to get his laptop and does a speed test. His laptop gets 34 mbps. Now my desktop is recently built with Realtek 1gb Ethernet port, but yet out of all the devices in my house, it seems to be the only one that has been limited. What do I do to fix this?