Hello @grandma4
Thanks for reaching out here in the Community.
A USB cable is a thinner cable connected to your Roku player that is responsible for providing power to your Roku device. The other end of the cable may be connected to either a wall outlet or a USB port at the back of your TV.
Since your Roku is detecting that it is not getting the sufficient power it needed to operate the device, we suggest making sure that the other end of your USB cable is plugged into a working wall outlet.
Some suggestions in this Support article may help as well: What should I do if the red light is flashing, or I see a "low-power" warning?
Let us know how it goes!
All the best,
Kariza
Kariza D.
Roku Forum Moderator