I am trying to install ROKU video streamer into my Sharp TV model 27KS300. Roku says to plug their red/yellow/white RCA cable into the video in ports on your TV. I do this but nothing happens. I am assuming these ports are the same ones I use to input the DVD player. ??

Yes these are the same yellow white and red ports that you would use to connect your DVD player. I believe this television has one port in the front and one in the back. I might be wrong but I believe video 1 is in the back and video 2 is in the front. If you have tried video 1 and video 2 making sure you have pressed the video/input button to select the proper one after connecting your Roku then you have done everything properly. Make sure to try a different RCA cable to make sure it is not the cable that is causing the problem. Also try the Roku on a different television because if it is working on a different television with the same RCA cable then you'll know that it isn't compatible with this particular television.