Blank laptop screen after attempt to connect to TV HDMI

There should be a key on your keyboard to switch between laptop and external display. You will have to read the instruction manuel to figure it out, since I don't know the exact model of your laptop.

-Bloc97

The shortcut key to toggle display screens for Windows 7 is "Start key + P", I assume it's the same for Windows 8.

But the problem is that he wouldn't see what he is selecting... On the keyboard, there is a key to enable/disable external displays...
-Bloc97

Both displays should not go black. May be different for desktop, but 1 display should stay on, till screens configured under "Screen Resolution".

There was cases of this before, the settings being messed up and the laptop not displaying on its own screen even after reboot. It is rare, but may happen sometimes, especially when he can access the user select menu.

-Bloc97

There was cases of this before, the settings being messed up and the laptop not displaying on its own screen even after reboot. It is rare, but may happen sometimes, especially when he can access the user select menu.

-Bloc97

What happens when you go in safe mode? If you can see your screen, re-install the display drivers in safe mode. (or at least uninstall it)

-Bloc97

Check HDMI input on TV and make sure it is on a right port. Restart the laptop without HDMI. The signal should go somewhere.

Try the RECOVERY method discussed here:
http://www.tomshardware.com/forum/3922-73-windows-black-screen-pointer

It sounds like a GLITCH where the NVidia drivers or Windows "thinks" you have it setup so your HDMI screen is working but the laptop screen is disabled.

Other:
1) Try a different HDMI cable
2) Try a different HDTV with HDMI
3) Press the F-KEY combo that TOGGLES which screen or screens is displayed (WITH and WITHOUT your laptop attached to an HDTV)

So Ive been looking all over for the answer to this exact issue and pretty every thread, or at least everyone of them that i "new tabbed" never seemed to get passed the diagnosis phase. So I had the exact same issue, running a Windows Media Laptop with a Win 7 64bit OS. If I connected the Laptop through HDMI or VGA, my laptop screen would go blank and it would go into some kind of "comatose" mode where it stayed on, yet the keys became unresponsive, so I wasnt able to do the Win+P shortcut to try and guess the display settings, and believe me, how I tried... on top of going through recovery options, safe mode, hot keys, all the way to my Measure and Click, which felt as ridiculous attempting as it is typing.

So this may not be a solution to everyone having this problem, but it turned out to be a really obscure solutions that made some sort of sense after the fact, and resulted in emotions ripe with hot fury. Alright I'm rambling, anyways, at one point my dad gave me a 20" hp monitor that he had no use for and since I had envisioned an unrealistic Mega Monitor Collage situation for a room that finally had room enough to accomplish it... least in theory. So the monitor has two inputs, VGA, and DVI which I've honestly never used, but all my VGA cords were in use and I just so happened to have an HDMI to DVI converter cord which worked as advertised, and for a month or so period of time I used the monitor as an extended display to my laptop. Now the 20" monitors prize setting is 1600 x 900 which to be honest until I plugged it in, was not aware that particular resolution at all existed. My laptop was set to its typical 1280 x 800 which the 20" grudgingly accepted with some loss of overall display surface area, but not enough to grind my gears, plus the display was pretty crystal clear. Fast forward a couple months later, I ended up using my laptop at work pretty frequently and sort of just stopped connecting it to the monitor. Another month or two passes and I end up moving rooms and Mr.20" HP 16 by 9 gets stacked with some other clutter which my rampant ADD forgot all about. At some point my laptop returns to room use and I plug it into different tv/monitors through VGA and HDMI with blank screens, "no display founds", and a repeatedly frozen laptop. The frustrating thing was the windows logo would come up, and after that, nothing. I was looking for a different cord and came across the DVI to HDMI one, which hadnt even crossed my mind to use and to be honest I may have forgot I had because seriously.... I got the A.D.Deez somethin fierce. I plug the thing into the laptop, and it starts up no problem, except I happened to notice that my laptop resolution settings had defaulted to 1600 x 900 upon connecting to another device which probably gave it the same reaction as I had when I saw it for the first time. I had messed with profiles, bios settings even though there wasnt much for me to mess with, safe mode scouring, hertz tampering, display setting overhaul, power settings tampering, monitor and tv resets, graphics drivers reinstallations, among other equally ridiculous trials and tribulations, and the problem almost fixed itself, or at least a solution presented itself by plugging in a single friggin display adapter cord. So if you end with this problem, and it really does suck because you can't see a friggin thing anywhere, nor are you able to alter settings within the necessary pc modes to do so, try thinkin a little obscure and outside the box, because the issue is most likely something you havent even considered yet. Im just glad I still have that adapter, because I do recall at one point attempting to connect the laptop to it through VGA with no dice. Anyways, god speed, good luck, and no this post has not been editted for grammar, spelling, incoherency, or any variation of the ramblins. I can't explain things and keep em short, somehow it just makes more sense in story mode. <3