I suspect the problem is with the HDMI-Composite adaptor, but just in case it's the Roku, maybe a restart of the Roku unit will correct it. If the scrolling prevents you from controlling things via the remote, pull the Roku's power plug for a few seconds then plug back in to restart. Otherwise you can restart via Settings > System > System restart > Restart.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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