Did you try connecting directly to your cable modem? That will be one of the first things Time Warner asks so I would go ahead and try connecting directly to the cable modem and rerunning the test. You may also want to try a new cable if you have one you could use.
Other then those I would say check the drivers for your nic, but that wouldn't make a lot of sense based on that it was working fine unless you had just recently upgraded them. If you have any other devices you could test with that would be helpful as well. Basically ruling things out until its narrowed down to being an issue with TWC.