HD TV not passing the tests offered on network tv

Which network? Cable? Satellite? Dish or Direct?
With any of these providers, you should get an ATSC or "digital" signal. If not, the problem would most likely be with the service provider since they are converting the signal for you. The only way that your set would be affected is if you have an "off air" (antenna) signal only. At this point you would need a converter box. If your service provider is providing you with a HD receiver, then you should have no problem recieving HD (as long as your paying for HD). However, keep in mind, digital is NOT HD. If there is an incompatability with your receiver, check with your service provider for a software or hardware upgrade. Also, check with your local TV serviceman to find out if there are any software upgrades (firmware) for your TV. Being three or so years old, it is possible.
One last thing to check is to see what type of signal you are passing from your providers box to your TV (which type of cable". At a minimum, you need a "component" connection to pass HD content. A "composite" signal is standard definition. Best you can get right now is an HDMI cable. Best "one cable" source for video and audio.
Good Luck.
Tim
Certified TV