Is this a laptop with an HDMI output? If so, you may simply just have to tell the laptop that you are using an external monitor.
Also, what is the make and model of the TV?
The TV is an LG 32LX2R-ZE. Its a desktop computer. It was working fine using the HDMI cable but not now. The Sky HD still works fine. I have checked the computer on a different TV and it worked so definitely problem with the TV
Then most likely the LG isn't handshaking withn the PC, and you should try unplugging the power to the LG for 30 seconds, plug it back in, and see if that doesn't fix it.
Also, even if your Sky box is connected via HDMI, it could still not work with the PC because of this handshake issue, so try that.
Let me know it that helps, and thanks for using JustAnswer!
Then you must have a defective HDMI input. I'm guessing your Sky box doesn't connect this way.
My only other guess is that the output from the computer got changed to a resolution the LG doesn't accept, but unless I'm mistaken, if it's an HDMI output it should always be compatible with an HDTV.
Short of getting a known good HDMI video device like a DVD player and trying it, the only conclusion I would have is that the HDMI input is defective, and that's certainly quite possible.
Well, then unless the computer is somehow delivering a signal that is incompatible with the LG, I have no explanation.
You could open your control panel and see if temporarily lowering the resolution to something ridiculous like 640 X 480 and see if that works, but again, I was under the impression that HDMI should not be prone to this incompatibility.
I do know that HDMI is fussy, and many times will not tolerate unplugging one source (your Sky box) and hot-plugging another HDMI source. You'd have to turn it off and then turn it back on again with the computer connected, but if this is new behavior, I'm afraid I have no idea.