Just got a Cosmos and the headset's not getting detected. Solid right light on the headset and SteamVR isn't identifying it. I've done the following:

>Unplugged and re-plugged all the cables
>Restarted the PC
>Shut down Steam, unplugged the cables from the link box and waited a few seconds before plugging them back in
>Tried to reboot my headset but I don't seem to have the option in steam; it just says "Please plug in your VR headset"
>Quit Steam VR and restarted the PC again
>Plugged each of the cables into different places (tried multiple outlets with the power cable and USB ports with the USB cable, although this PC only has one DisplayPort so I didn't get to try with that)
>Took the whole thing over to my other (less powerful) PC in another room that I know works fine with a first-generation Vive and I got the same issue

I've got Steam VR installed but not the Vive app. Is there anything else I should be trying here or is this headset DOA? I'm at a bit of a loss.