How long have you had the Roku box for and when did the problem occur?
Have you checked the remote IR to see if it's functioning?
If not, then use a cell phone camera or digital camera and look through the viewfinder (with the camera ON), point the tip of the remote at yourself and press any of the buttons. Do you see a bright white flash when press buttons, and viewing it through a digital camera?
Can you please reply back to the rest of the Info Request?
Specifically how long have you had it for and when did the problem occur?
Also, please get me the exact model of the Roku box (located on a sticker).
You have a faulty remote control. If you did not see the bright flash, then that means the remote is not sending it's IR signal to the Roku box. The Roku is covered under a 90 day warranty. What you need to do is contact Roku and have them send you a new remote controller for the box. The link below contains all the information you need to get another Roku remote: