For the one with the purple cityscape you may just need new batteries in the remote. Does the remote have a button on the back or inside the battery compartment? Are these Roku TVs or Roku devices connected to TVs? You may be able to try the remote from one device on this one that just shows the screensaver. Unplugging the power and plugging it back in should get you to the Home Screen until the screensaver activates.
The one not connecting is tougher. It may just be too far from your router or it may have a malfunction. When you go through the process under Settings->Network->Set up connection do you get any error messages or codes?
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