No idea what or how but seems strange, been seeing near identical like your post cropping up every weekk from 2008 owners. They had trouble early on (first two months) with freeze on wake from sleep for one thing. There were SMC and EFI updates, later models had that rolled in and improved motherboard. (One reason to hold off for first 3-4 months for revisions based on early reports to be fielded).
You or someone else with power strip, my suggestion is avoid those things and get a solid 1500VA UPS w/ Sinewave, if nothing else but I thiink they improve and prevent by providing the PSU with good clean power all these 4 yrs you've had yours or the 6 yrs I've had mine.
Other than reset the motherboard SMC and playing around with Risers and DIMMs and running AHT, even try running 10.5.x off your OEM DVD on a freshly iniitialized drive - just to see and test it works with the original OS! worth a try to have clean bare hardware and OS.
Thanks for your reply.
It doesn't get far enough to do anything like boot from DVD, or open DVD tray holding left mouse button on boot up.
The flashing LEDs on the memory trays indicates to me it hasn't got far enough to locate and configure all the memory.
It flashes the LEDs for all 8 DIMM slots. I only have 4 populated. So I'd guess the trays are saying that they are not yet configured.
I will try removing unnecesary stuff like SSD PCI card drive, eSATA adapter etc and see if that helps.
If you can get one pair of DIMMs working with just one Riser.
you don't need any hard drives if that helps - AHT just needs "something"
Amazon has 2x2GB $54, 667MHz work fine and can't notice 4% difference.
I don't know of cheaper - outside used & ebay market.
I've found it!
The OWC PCIe SSD drive that was my boot drive was the culprit.
I removed all unessential internal PCIe and external devices and it booted.
Adding back just the SSD caused the problem.
I can understand why a bad card/device could cause it to fail at boot time - but with Over Temp indicators - weird.
Installed/attached everything else and it booted several times and up for 30 miuntes now.
Keeping my fingers crossed!
you are neither the first or last w an ssd issue.
I'd look into firmware for one thing, just like firmware affects your PCI contrller would.
you must feel like you're floating after looking into dark pit of *** happened.
system hardware profile was nice to have, profile should have complete list
so you got this right after...? upgrade to 10.8.1 from 8.0, or from 10.7.4?.
Just adding to the record. Your post helped me solve my issue.
I experienced the exact symptoms on my early 2008 MacPro 2.8. Detaching my SSD nor any of my 5 internal HDs solved the problem. Disconnecting my external Samsung USB-connected Blu-Ray writer returned things to normal. The OT lights and failure to start must be related to some improper signal that is encountered while the computer searches for startup drives. I'm just surprised it happens the moment the computer is powered on and not 1-2 seconds later.