I just got off a chat with someone from the helpdesk who advised me to go to system settings and check for an update. I would've done that straight away, but it had said that an update had already been done this morning (since the problem began).
But now i've done that, it seems to be working fine. Hope this helps.
I was told initially to unplug/plug back in. Then they suggested holding the reset button. Neither of those worked for me. But checking for updates appears to have fixed the issue on both boxes (for what it's worth, we have the old black boxes with the blue writing).