After switching between an hdmi/vga my display quality dropped

[mORTcube]

So, recently i bought new monitor the BenQ GW2320, it came with an hdmi cable so i plugged it in and all worked just fine, but from time to time the monitor lost signal from the GPU, so i tried the VGA cable, the display quality was absolutely awful so I tried the hdmi again, but for some reason the quality is much lower, its all blurry and there are some weird lines at the startup and dots in the bios and the maximum resolution option has changed. The monitor is FullHD, but now the maximum resolution is 1600x1200, also there are only 4 options available.
Also in the device manager, monitor disappeared and some yellow triangle has appeared next to the GPU.

My gpu is GeForce GT 630 1GB
I reinstalled all the drivers for GPU or Monitor but nothing helped.

There are pictures of the screenresolutions http://s29.postimg.org/v8ac3p2tz/Resolutions.jpg
Device manager http://s28.postimg.org/djtzhn3wt/Device_manager.jpg

 

[Ironsounds]

Hello... try another HDMI cable? there are Quality issures with HDMI cables, check before playing with drivers or software...

 

[mORTcube]

Alright, so I tried different cable, but the problem was still there. I thought that it might be just a broken monitor so i changed it for a new one, but the problem is still there.

 

[Ironsounds]

Hello... there is a Device info file... its not a driver, as a monitor is a passive device... But it will let Windows know what the screen resolutions the monitor has available AND the name/brand, of the monitor, for Windows to display.
Also you need to load the Device Driver for your Video Card, to remove the "yellow Triangles" go to Nvidia Website for the proper driver for your card and Windows OS http://www.geforce.com/drivers

 

[mORTcube]

I Installed the newest Nvidia non-beta driver for my graphics card but the yellow triangle is still there.
Also where do i find that Device info file?

 

[Ironsounds]

Hello... was there a "support disk" in the box of your new Monitor?

 

[mORTcube]

Yes, there was one.

 

[Ironsounds]

Hello... it's on there... also reseat your video card and see if Windows loses the yellow triangles.
How much experience do you have in installing drivers manually? using the "Device Manager" ?

 

[mORTcube]

Hello, so i think i actually might solve the problem. Drivers were just fine.. but the Graphics card in the case wasnť exactly placed right and the connection between the cable and graphics card was bad. I actually managed to get the 1080p resolution back, drivers are working, but now there is that problem what i had at the start. Monitor just randomly loses signal to GPU.. Maybe the GPU is bad? Because when it does that, the monitor just turns off, and even if i try to plug the cable out and back in again, the signal doesnť recover.