I have had problems with my Roku remote about a month after we got it. It won't work at all anymore. The pairing light isn't on and a fresh pair of batteries didn't do it.
I have done:
Repair (when light was on)
Unplugged my devices
Several sets of new batteries
I now don't have a working remote at all.
You have to make the pairing light come on, by pressing and holding the pairing button in the battery compartment for 5 seconds and release, let it communicate with Roku. And you would still have to press the pairing button for 5 seconds even if it already blinking.