Make and model of your tv may help others to help you. Meanwhile, things to try:
In the tv settings look for something labeled "split screen", "picture in picture, "PIP" or similar, and turn it off.
For the black and white issue, find the "Color" setting and make sure it's not set too low.
- Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
- Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T
- TCL Roku TV 43S425/C107X, Ser X000001R60KV, wifi