no ip

Hello all I am having a issue, so I put a little 8 port switch in the wall jack which is connected to a 24pt Cisco switch, on the initial install of the switch I connected 4 pcs all of which could access the internet and would pull and IP, However now about two weeks later I was called about these four pc’s none would connect to the internet, I noticed that IT guy that was there changed the DNS from automatic to a static, now I put it back to auto and the first two pc’s grabbed an IP however the third and fourth will not. Only two pc will get an ip now where before all 4 got an IP with no problem. I changed the 8pt switch same problem so its not that switch, can anyone help me isolate this issue?