Can't get display to work, white flashing light

I am replacing an older streaming stick (starting to fail after 4 years) with a Roku express. When everything is connected, the Roku load up screen comes on for a few seconds (with sound) then disappears. The input is no longer detected by my tv, and I start getting a white light flashing light on the Roku. Research suggests that it’s a bad internet connection, but I can’t even get the display to stay on long enough to get to settings to input the wifi password.