Blue light steady for about 10 seconds, then blinking also 10 seconds, then off also 10 seconds then continually repeating this cycle. When I click on an app, Roku jumping letters appear, then after a while the app screen returns. When I click any app again get a "loading" msg, but after a few seconds the Roku jumping letter screen returns. Good strong internet connection.
Do you have it connected to the TV's USB port or are you using the supplied USB power adapter? If the former, try the supplied power adapter. If the latter, try the TV's USB port or preferably another power adapter/charger from a phone or tablet that can supply at least 1 Amp.