Roku setup

[nchamp]

I set up Roku Express 4K box on a Sharp Aquos with one HDMI port. When I attached another HDMI cord from my computer, the computer cannot recognize the TV. I've tried everything, including using a different computer and HDMI cord.

[renojim]

I assume you're disconnecting the Roku to connect the computer otherwise I don't understand how you could connect both.  Try unplugging the power to the TV for several minutes (don't just turn it off and on).