BluePearl
If you have the option, try connecting the Roku device to another TV and see if it will load properly. If so, then manually set "Display Type" (Settings/Display Type/720p.) Then place device back at the problem TV location and see if it will now load properly. Roku sometimes has issues with the auto-detection of display types. (especially after OS updates).
If the above does not work, or you do not have an additional TV to perform this on, then try Factory Reset of the Roku device. Press and hold the Reset button for 30+ seconds while device is powered. During the setup and activation, manually select the Display Type. (again, start with the 720p and do not let Roku perform auto-detect).
***Verify you have a working Roku Remote (or compatible physical remote) before performing Factory Reset on any Roku device.***
Also, if not equipped with a power adapter, try using a cell phone USB power adapter and try powering the Roku device from wall power (rather than TV USB power port) and see if it helps. Any 5volt, 1amp power adapter should work.