I feel for you guys. Purchased a RXZ7 in March 2009.
My Z7 died back in July 2010. The receiver would only power up via the main power button. I contacted Yamaha Support, and was provided with a link to put in my zip code and take my unit to the nearest service center.
It took six weeks to replace the digital video board. When I got the unit home, I noticed several screws from the back missing.

I also had the firmware error and had to reload.
Over the past couple of months, I have noticed that my presense speakers do not always work when they are supposed to. About 50% of the time, I have to shut the receiver off, then turn on - then the presense speakers work. I contacted Yamaha Support and was told the processor requires repair. I was provided with the same canned message to click on link, enter zip code, and take unit to the nearest service center.
I am somewhat lucky as there are 2 service centers in metro Detroit. I will not be taking it to the service center that I used previously. So, I will reluctantly try the other service center. I foresee my receiver being gone another 6 weeks.
I have owned other Yamaha receivers and never had an issue. The Z7 has made me sick - I spent alot of money on a "Flagship" receiver that gets little support. Yamaha does not care - they have our money. They have no intent on making it right.
I guess while the Z7 is out for repairs, I will start researching various brands of AVRs for a replacement - and Yamaha is no longer on my list.