@MissHall, it wouldn't hurt to try another USB power adapter/charger from a phone or tablet and/or another USB cable. Look at the fine print on the adapter for something like, "Output: 5V 1A (or 1000mA)". Anything greater than 1A/1000mA is all right as well, but less is not. After that, about all you're left with is a factory reset, but note that if you've been using the app as a remote you must have a functioning physical remote to set up a device after a factory reset.
How to system restart or factory reset your Roku streaming device | Official Roku Support
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