Monitor no signal with HDMI to PC

[Vivac93922]

So, I've been using my PC for a couple months with "dual monitors", one being an all in one pc and the other a BenQ RL2455. I've used them both far for the past couple of months, but earlier I restarted my PC and when I booted up my computer the "all in one pc" or my second monitor said no signal.
Extra info: My all in one is connected through a HMDI and the BenQ through a DVI-D cable.
The monitor doesn't even show up in device manager under displays and I tried booting in safe mode, but it still didn't show up.

 

[Greg Gregorich]

check cable connection.

 

[Shaun o]

What ever brand of graphics card you are running, go into the software app that controls the video output.
The likely cause of a message like no signal, can be down to a fact that for some reason.

A. The display resolution for the second monitor has changed and needs to be set in windows again and the video card software app or driver suite.

B. That the monitor resolution in set correctly, but the refresh rate at the set resolution is set wrong, and needs to be lowered in the Hz range.

Any resolution set, that is set above the Hz range the monitor can display at will give a message of No signal.
You will no likely find if you have the correct resolution set, it will be the Hz range that is your problem for the resolution chosen being to high.

You should also swap the old cable out and connect a new one to confirm the cause is not a bad connection of the video cable being at fault.

 

[Vivac93922]

What ever brand of graphics card you are running, go into the software app that controls the video output.
The likely cause of a message like no signal, can be down to a fact that for some reason.

A. The display resolution for the second monitor has changed and needs to be set in windows again and the video card software app or driver suite.

B. That the monitor resolution in set correctly, but the refresh rate at the set resolution is set wrong, and needs to be lowered in the Hz range.

Any resolution set, that is set above the Hz range the monitor can display at will give a message of No signal.
You will no likely find if you have the correct resolution set, it will be the Hz range that is your problem for the resolution chosen being to high.

You should also swap the old cable out and connect a new one to confirm the cause is not a bad connection of the video cable being at fault.

Ok, I've already tried changing the cable. My monitor doesn't even show up in my device manager. Also, I just reinstalled WIndows because I got some huge virus and it's still not showing up.