Thank you for trying,
Unfortunately that confirms an internal hardware failure. The system is shutting down as part of a protection mode to prevent further damage. There is a fault in the power supply or a short (dc offset condition) in the output stage of the amplifier.
This can happen as the result of damage from a power surge, but is also often just from normal age related wear and tear. I know you said 7 years old, but this is a 2003/2004 model, so it is actually at least 12 years old at this point, and well over doulbe its service life.
While it is possible to fix, it is simply not practical or worthwhile to do so, repairs will easily run you several hundred dollars, more than enough to replace it with a brand new model with updated features (hdmi, networking, etc) and a fresh warranty. That said, I can help with finding a repair shop or replacement recommendations, whichever you prefer.
My apologies for the news.
If you have any other questions, just let me know. Otherwise, please take a moment to rate my service as this is the only way I am credited for my time. Hopefully I have earned 5 Stars but if not please let me know what I can do to ensure you are satisfied. I also invite you to contact me directly with any future support needs at http://bit.ly/1QwLxGh and ask for Nathan.
Thank you, ***** ***** a nice day,