HDMI shows no video

I have a Benq 24" monitor and an HP dm4 that I just bought. I can get perfect 1080p video from VGA but when I plug in the HDMI cable, I hear a "dun dun" sound on Windows 7 as if I plugged in a USB but no video, and the monitor says no signal. I tried changing the source on the monitor but it doesn't work. How do I do this?

 

Just went through this today with my Asus monitor. It's a weird little deal--You have to be hooked up to the VGA cable to change the source. Once you reconnect the VGA, you can change the source to HDMI, and away you go.

I couldn't even access the on-screen menus, since the display kept going to standby because of "no VGA signal". Benq may be doing the same thing, since a lot of the chipsets are the same across several brands...

 

Try checking your display settings in Windows (You have ATI, try Catalyst Control Center). You're monitor and the cable is probably fine, you just need to tweak a setting or two in Windows (or update your graphics drivers as well).

For the record, Catalyst Control Center has an option where it will NOT automatically detect new, connected displays, if this is the case, you must go to the Desktops & Displays tab in the CCC and manually select the "Detect Displays" button.

 

This worked, however on my monitor when I put it to max resolution (1080p) it doesn't fill the screen. Putting it to 1600x900 fills it but makes it blurry.

 

You should be able to correct this on the monitor. Set it to auto scaling/size or something like that.

 

Auto scaling is disabled for my HDMI for some reason