HDMI port on motherboard but cannot use it? Help!

I have an Acer Aspire AM5640. The motherboard is model MCP73PV according to CPU-Z.
There is an HDMI port on the motherboard/back of the computer, and I would like to use it to hook up my PC to my Samsung HDTV.

Now, I have an ATI Radeon HD 3450 that came with the computer.

I've hooked up my PC to my HDTV before via the VGA port, and it would automatically detect my TV and display the desktop on there, but now for some reason it wont. I haven't tried hooking it up to the HDTV for a few months, decided to do it today, and it wouldn't work. It says "No Signal".

I've tried using the VGA port on the graphics card and I get "Mode not Supported". If I try to use the HDMI port on the motherboard/back of the computer, I get "No Signal". This seems like a big difference in errors and something that's causing me trouble.

So, my question is; how can I use the HDMI port on the motherboard/back of computer to hook up my PC to the HDTV so I can view 1920x1080? I've had 1920x1080 via the VGA port, but now I cannot do it for some reason, as mentioned above.

I'm really at a loss at what to do. I've tested the HDMI cable, and the VGA cable with another PC, and the cables and HDTV works fine. It's definitely something to do with my PC.

Please help me as it's really frustrating. Thanks and sorry for making the post so long.
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More about hdmi port motherboard help
  1. If you ONLY connect the PC <-HDMI-> HDTV with no other video connections to the PC and restart the PC does that work?

    The HD 3450 comes with HDMI so use that connection; failure try either upgrading or downgrading the ATI drivers.

    The HDMI includes both video + sound and is digital so it's the 'ideal' connection. You TV has to support 1920x1080 otherwise you will get "Mode not Supported" error. Older 'HDTV' were 1280x720.

  2. My Samsung HDTV supports the 1920x1080 resolution as I said before. I've used 1920x1080 on the TV with the Acer before, and today I tested it again with another PC. The cables, and HDTV are both working fine.

    My HD3450 doesn't come with an HDMI port. It's a Saphire ATI HD 3450 256MB. It has S-video, DVI and VGA.

    I've tried only connecting the HDMI cable and restarting, to no avail. The message I get is "No Signal".
  3. Pull {remove} the HD 3450 and try again. Resolution - just making 100% certain ;)
  4. That works. The HDMI port is picked up, and since it was the first time, it installed the Nvidia drivers I think.

    However I have another problem now; no sound. Even through the speakers port it doesn't work. I tried to set the HDMI Audio Controller to default in the Playback Sounds window/mixer but it doesn't give me that option; the "set to default" setting is greyed out.

    Another question; why is it that when I try to plug in a VGA cable to my HD 3450's port and hook it up to the HDTV, it doesn't automatically work? The booting screens are shown, but when right when it finishes loading the Windows loading screen, it shows "Mode not supported".

    How can I change this so I can at least use 1920x1080 via the VGA port until I get a new gfx card that has an HDMI port?

    Thanks again.
  5. Most of what you are describing seems to be either Driver related and/or corruption of the drivers and their registry entries. Typically in the Device Manager - uninstalling the Driver(s) and a restart {or re-scan} will re-install the drivers and correct registry errors. However, if you upgraded the drivers and some {parts} of the older drivers remain then that too can add to corruption; see Driver Sweeper below.

    If the 'HDMI sound' is grayed-out then my assumption is the drivers for the onboard video are either wrong or not completely installed. You'll need to go to the Acer's website and download the most recent drivers or use the older drivers that came with your PC.

    RE 'Another question', basically the same as the first problem incorrect drivers. As soon as Windows boots the drivers aren't loading properly or are the incorrect drivers.

    The HD 3450 ATI/AMD drivers are the easiest to obtain -> http://support.amd.com/us/Pages/AMDSupportHub.aspx

    Answer - VGA, re-install the HD 3450, in the BIOS make the PCIe initialize prior to the onboard iGPU, Disable the iGPU in the Window Device Manager. Download and install the latest ATI/AMD drivers then restart. Shutdown then connect the VGA to the HDTV as the ONLY video connection from the PC and restart.

    If necessary remove possibly corrupted drivers using Driver Sweeper -> http://phyxion.net/Downloads/

    As stated "HDMI includes both video + sound"; HDMI 'should' disable ALL other sound output. This is to avoid the video and sound being out of 'sync.' Again, if grayed-out it's a driver issue.
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