I have a Mac Pro 1,1 (dual 2.66, 4x1 GB memory, GeForce 7300GT) which works fine except that when it has been turned off for any length of time e.g. overnight or even just an hour or so it seems, although left plugged in, when next started on the first attempt the power light and fans come on as normal but I don't get the boot chime or a signal to the display, and the red light next to CPU B Error on the logic board comes on a couple of seconds after pressing the power button. If I hold down the power button to turn it off and then immediately start it again, it always comes on perfectly the second time, it never takes more than two attempts to start. It doesn't need to have been on in its non-booting state for any length of time so it's not an issue with components needing to warm up first. Once running, if I shut it down and then start it again relatively soon afterwards (eg 10 minutes later), it starts up fine the first time, the problem is only after longer periods unused. This is absolutely baffling me as I have done extensive searching but can't find anyone with the exact same symptoms, and I have only had the machine for a few weeks and it was working perfectly to begin with, this has only started more recently but it is consistent i.e. it only starts second time if it has been off for a reasonable period of time. I have already tried the following: -- Replacing the logic board battery with a new one -- PRAM reset (Cmd+Opt+P+R at startup and hold until two boot chimes have sounded) -- Starting without the SSD being connected, this being the only non-standard component installed SMC resets there seem to be a lot of possible ways to do this on various sites, so I have tried all of these: -- Unplugging for 15 seconds, plugging back in and waiting 5 seconds before starting up -- Unplugging, pressing the button on the logic board just below drive bay 4 for 15 seconds -- Pressing and releasing immediately the button marked "SMC_RST" behind the memory cards, with the machine still plugged in -- Unplugging and holding the front power button for 45 seconds If anyone has had an issue like this before or can provide any pointers it would be much appreciated!