Cannot connect to internet in one location

I am working on a computer that had malware in it. I removed the malware and took it back to the owner only to find that it would not connect to the internet at that location. They have another computer that works fine and the cable company came and checked and all is well with their part of it. The computer with the problem connects at other locations so I'm thinking there is some kind of block causing it not to be able to use that cable modem or at least the IP address. I have checked for more malware and am running an online virus scan at the moment to see if there is something in it that is stopping it. If anyone has any suggestions, please let me know.

Thanks