# Mac Pro freezes on Boot Up



## stinkmink (Oct 30, 2010)

Hello Everyone
The other day I got the dreaded black screen with the multilanguage "you must restart" message. I did so and now the machine boots up to the grey screen with the Apple logo and spinning gear and freezes.

I can see the drives when I put the machine in target mode and connect to another mac via firewire. I took this opprotunity to back up all the important stuff and ran diskwarrior. Some problems were found and repaired. Still no boot.
Did option+command+p+r to reset the NVRAM/DRAM, still no joy.

Holding the shift key during bootup gives me the panic message "Unable to find driver for this platform: ACPI" Darwin Kernel message as well as the "You need to restart" message underneath. 

Using the installation disc I did a hardware check, all OK.

Since back up was done, I decided to wipe the system drive via firewire and had disc utility verify. It did the format but said it couldn't complete the task, so I figured maybe the drive is on its way out with bad sectors or something. Aquired a new drive, installed it, but machine will not boot off the install disc (OS X 10.4.7, yes I know it's old, but it has been satisfactory for my uses). Same Apple logo on grey screen freeze.

I have 4 512 RAM chips which I swapped out in pairs, no change. I can still do the hardware check and see the disc when holding option during boot up so I know the DVD drive is OK.

Anyone seen this before? Clearly there is something fundamentally wrong and I really don't want to spend wads of money on this.

Any help or suggestions would be much appreciated.
OS X Tiger 10.4.7, Mac Pro, Dual Core Intel Xeon @ 2.66 GHz, 2 Gig Apple RAM


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