Get a universal remote. They are easy to set up and there are many options with varying prices and features

You should be able to contact the manufacturer & request a replacement, they should do this@ no charge, otherwise, I'd go back to the business of your purchase& request they get you a remote from another unit so, they can return to vendor the tv they took the remote from to give you, unless they're more comfortable replacing your unit entirely

You can't... directly. Red and white are for sound (these match up with component) and yellow is for picture (the red, blue and green). In the component input that you describe, the system is looking for the visual to come in through a component breakdown of primary colors. You will need an RCA to Component adapter or an upgrade to the device that you are playing from. Good luck!

"YES" you MUST use The "INSIGNIA TELEVISION REMOTE" Press the Input Button after you Put the ROKU in to the HDMI Slot and USING the INSIGNIA REMOTE Press the input using the arrows on your remote got to HDMI 2 or HDMI 3 then press enter depending on where you which HDMI Port you Plug the ROKU stick In to and When your all Done with the ROKU To get Back to the Television Using your INSIGNIA REMOTE Press the Input Button and using the Arrows go to TV and Press Enter " IT IS VERY IMPORTANTHAT IT IS THE INSIGNIA TELEVISION REMOTE Not Any other ( any other question or for more Info you can Call Best Buy at 1 800 Best-Buy

I think it would be normal to have a bad picture if not a HD source. Hooking up cable produced the same outcome but when hooked to the Playstation 3 with a little TV calibration, a good picture. Would not recommend for standard definition as the picture will not be what you are expecting.