I ran into this problem this morning after trying to spend hours to fix it. I found a fix online and thought I would post it here if anyone else has the same problems. Just want to thank mcdougal806 for posting this fix on Tom's Hardware.
ASUS "HDMI No Signal"
THIS IS A FIX
I had this issue today with my ASUS LCD monitor. I called tech support and they couldn't help me at all, they recommended an RMA. I checked online and couldn't find anything either. I fixed it... it is extremely simple!! I want to post this online for others having this problem. At the moment, the ASUS website is down, or else I'd be posting it on their forum.
If you are having this issue, press the button just to the left of the Power button, it will cycle through the available inputs. Press it until you see your desktop...
The manual does NOT say anything about this button, and it is not marked well. One thing I cannot believe is that ASUS actually told me to RMA the monitor... I asked them repeatedly "Are you sure there is not anything I can do to fix it?" and they just kept telling me that it was a "known issue" and that an RMA would likely be the only solution.
So, if you are having this problem, press the button to the left of the Power button and it will fix it!
Tell you what, I almost had a stroke over this. It's my birthday, and I thought my monitor died. I was in disbelief, and am still in disbelief over the service I got from customer support.
What's more? The manual included with the monitor does not even give a customer support phone number, or any type of troubleshooting, I had to go online to find it on my laptop. I found that an unfortunate amount of people were actually RMA'ing the monitor. I want to post this to help anyone having this issue.
Just wanted to thank Bushpilot223 from another site that i went and did some researching from. If anyone ever has this issue here is the easy fix. My hand or my printer must of hit this button and put it into hdmi mode not the vga or dvi mode it needed to be in. I would like to select this as my best answer for my question