If you get the chance, please include a screenshot, but does Windows show any message when you put your mouse over the sound icon?
I've seen a muted speaker icon, but don't remember seeing an 'X' unless this is what you mean.
Try right clicking the speaker icon to select 'Playback Devices' if you haven't already.
Assume you are running Win7 and the notebook speakers work okay, but if you haven't checked device manager, make sure you aren't seeing any errors for the sound or vga and tell us the driver versions you are running for the vga and audio if possible.
If there is an easy way to try other HDMI cables, TVs, or a different system with your TV, you may want to compare this way too.
Good luck!