If the power went out and you don't have your set top boxes on good power bars / surge supressors, it's entirely possible that when the power came back on that there was enough of a power surge to possibly fry the box. If that basement box is moved upstairs and it works there, then the cause of the issue will be harder to determine. If it doesn't work, it may need replacing. Your best bet is to contact Telus and see if a tech can come out.
It's possible updates are being applied to the boxes. If they haven't been restarted in a long time they get applied when the box is restarted. Depending on your link speed it can take some time to complete.
I noticed the sequence to turning on the boxes makes a difference.