I have a Roku 2 that had been working fine until 2 days ago and now it suddenly will not turn on or connect to the TV. I have tried power cycling it and factory resetting it, both with the same result; the white line turns on solid, then blinks, then turns off completely and when a button is pressed on the remote to try and wake it up the white like blinks rapidly but then does nothing. At no point is there a picture on the TV or does the TV register a connection to the Roku.
There are several models called ROKU 2. Which do you have? All Roku models listed here:
https://developer.roku.com/docs/specs/hardware.md
Look like the newest came out in 2015. That's pretty old, You ROKU may just have died.
It says model 4210X on the back of it.
It or its power adapter could have gone bad. I'm not sure it's worth buying a new power adapter given its age, but if you have another one from a Roku 2 or 3 (42xx models) it might be worth trying. I don't usually recommend a factory reset, but given that it's not working at all you don't have anything to lose. With the power connected, press and hold the reset button with something like a paperclip for no less than 30 seconds.