Dual monitor HDMI leading to black screens

[H-Cue-]

Hey guys,

I got a super annoying problem right now and even after searching, I couldn't get it fixed. Currently, whenever I plug the HDMI cable that connects my external monitor to my laptop, BOTH screens go black and I can't do or see anything in either.

The story is like this: I got a new monitor to go with my laptop. First I plugged the new monitor in via HDMI and it all went smoothly, both screens working and image showing. However, I noticed the mouse was skipping a lot on the new monitor and a quick check showed that it was running on 30hz. Since I could not select 60hz (which is the frequency the laptop runs in), I went into the nvidia control panel and created a custom resolution for this new monitor with 60hz. That's all I changed. Windows said it was gonna "test" the new resolution, it did and said it was all ok. So my problems were all solved, mouse not skipping anymore and both screen working well. So I made the big monitor my main monitor.

A few minutes later, however, the external monitor stops showing my desktop and displays an error "Input Not Supported". I don't know why at all since both screen were on the same frequency and the big monitor can go up to 75hz. The big problem then was that whenever I had the monitor plugged in, it would become my main monitor, which meant I couldn't see any windows that would open. For instance if I opened Display settings from the laptop screen, the window would open on the big monitor screen, which is black, not allowing me to see or change anything. Then I don't really know what happened but both screens started going black the moment I plugged the HDMI. And even if I unplug it, the laptop screen continues black and I hear my laptop fans going crazy.

I have no idea what to do, I tried some boot changes, booted in safe mode but didn't really get anywhere. For some reason the 60hz of the big monitor is causing trouble but I cant access the setting for that monitor without having it plugged to my laptop, which turns both screens black now...

Any clues? I'm really lost right now... any help will be greatly appreciated.

PS: Laptop Clevo x7200 (1920x1080 @ 60hz) and new monitor IIyama XUB3490WQSU (3440x1440 @ up to 75hz).

PS2: Now when I start windows 10 on my laptop, when the windows logo is displayed and the little loading circles are spinning, the screen goes fully black for about 1 second, then goes back to the logo and windows loads fine. This never happened before and I'm not sure if it's helpful or not to say it.

UPDATE: I did a clean reinstall of the GPU driver and that deletes all profiles created, which I think is why it's working again now, it can't find the 60hz profile for the big monitor anymore. So now Both screens are working again. I'm going to create a new post about how to actually get my new monitor @60hz without ruining everything.

 

[mbilal2]

My best guess is that your graphics card simply cant handle the load of running two screens at once and that is why it is causing so many issues. When you were getting two black screens, the GPU was trying to sending the video to the secondary display. You had to press (win+p) and "guess" which option said "use PC screen only". This would have moved the display to the laptops scree.

Once the external monitor was selected as the primary, you just had to right click on the desktop, click display options and select your laptop screen as the primary display but you couldn't do this since you couldn't see the display on either screens.

Your GPU can handle the display on your current screen and that is pretty much it. It tried it's best to give you the best display it could on the secondary screen (which was at 30Hz) but then you forced it to run the laptop screen at max settings AND your monitor at 60Hz. This made is go crazy as it was more than what it could handle.

Hope this helped.

 

[H-Cue-]

I think you're probably right. I am only running a geforce 480m GTX, so that might be the case. It's good to knwo about the win+p thing, that would've come in handy before everything else went bonkers. Thanks!