I have a Dell Studio 1558 that is still under warranty. Today I went to hook it up to a HDTV through the HDMI port and the TV said no signal. Since I bought this laptop this is the first time I'm trying to use the HDMI port. The problem is with the laptop because I also have a Studio 1537 that work with this TV. Also, when I plug in the other laptop (studio 1537) I hear the tones for a new device and in the Device manager it show two monitors. When I plug in the Studio 1558 I hear nothing and device manager shows only the built in monitor. I have tried extending the display but still am having to luck.
I am sorry to hear that you are having problems with HDMI with the notebook.
Jimco has a great FAQ regarding troubleshooting HDMI issues, here is a link.
So cutting and pasting from the FAQ are the basic steps when connecting HDMI
Connecting the laptop to the TV
Every time you try a different solution you should reboot the computer using the following procedure. As our former moderator Dell-Bill B wrote: "HDMI audio is pretty picky and doesn't seem to work well without a reboot, in general."
Also the computer should be off when connecting the HDMI cable.
1 Turn off the computer and TV.
2 Connect the HDMI cable to the computer and TV.
3 Then turn the TV on. Adjust its setting to receive HDMI audio.
4 Next, turn on the computer to allow it to detect the connection to the TV.
5 Go to Start>Control Panel>Sound>Playback tab. Select the HDMI device as the default device. Click the Set Default button, and then click OK.
Since you have tried the TV with another PC and it worked, I was wandering if you have tried this system with another TV to make sure that there isn't some type of compatibility issue? Have you tested the system with a known good HDMI cable?
With the assumption that there are no compatibility issues between the notebook and the TV, the HDMI cable is known good, my suggest will be to reinstall the video and audio drivers and try again. If that fails I would suggest having the system board replaced.
Specialize in Laptops, Mobile Devices