First: you need to provide more specific info on your Roku device. Is it a Roku stick? If so what model? or is it a Roku TV? or a Roku desktop device (again provide model number.)
In my opinion since your other devices are working is that somehow the network configuration on your Roku device got corrupted. You can get the info to put into your Roku configuration from one of your working devices. The router ip (aka default gateway or simply "gateway), and dns settings should be the same on both devices.
The first three segments of the device ip (or simply "ip address) should be the same. The last or fourth segment can change from time to time because it is negotiated thru dhcp. You don't need to worry about the last segment.
The subnet mask setting will almost always be 255.255.255.0
I had a similar issue recently with an older stick. It started out as intermittent disconnects during programs and streaming interruptions that would self correct after a few seconds. Some times it would jump completely out of a channel or reboot itself as time went on and the problems increased. Finally it just quit. It was pretty warm to touch so I assumed a component failure due to, or as the cause of the heat. The only solution was to replace the stick with a new Roku device.
