I have an 8-core Macpro with an ATI X1900 video card. I came in this morning and pressed the power button and was greeted with no startup tone and no video at all. I have tried removing any extra hard drives (in fact all of them at one point.) and RAM so it is configured as I got it from the factory. I have followed the instructions on Apple's site re: reseting SMU, but this was quite confusing. Firstly I left it unplugged for a few minutes which should do it. Then I tried manually resetting it but I am not sure I have located the button correctly. In the article it says the reset button is located below and to the right of a row of diagnostic LEDs but I am not sure exactly where they are! So firstly any help locating this elusive button wold be appreciated. The only button I can see on the motherboard is just above the highest PCA slot so I am assuming it is that. If it is, I have pressed it and still no joy. A couple of other things to note: there is a dvd in the drive at the moment and I have tried to eject it by holding down the eject button during startup but it won't eject (I was trying to see if I could boot of the install dvd) In fact I have no red light on the underside of my mighty mouse either so I don't think my computer is even getting that far. Also the fan on the X1900 sounds like a small tornado so there maybe an issue there. Any ideas would be appreciated before I head off to my local (or not so local in my case) Apple store for a repair. You never know I may be "lucky", if they do announce new Macpros today at the WWDC, and my problem is terminal, then I may get a new one as a replacement (as I did with my MBP a few months back). EDIT: So I think I have located the SMU reset button, it is behind the RAM slots. Still no joy though..