The Roku remotes with TV controls are two remotes in one - one for the TV and one for the Roku. It's possible for one set of controls to work and not the other. It sounds like your remote is not longer paired to your Roku device. Disconnect the power to your Roku device, press and hold the pairing button on the back of the remote or inside the battery compartment (or press and hold both the Home and Back buttons) until the light on the remote starts flashing. Reconnect the power to the Roku device and it should pair. Don't assume that the batteries in the remote are good just because the TV controls work. You may want to try new batteries before you try the pairing process.
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