Why might OS X suddenly stop booting? Off HDD and DVD?

[CrArC]

I have OS X running on an MSI P35 Neo mobo (known to have an ACPI incompatibility without the very handy modified BIOS released by a user of this forum) and everything has been fine until this morning when I did a routine reboot and the system would not even show the darwin bootloader.

 

This didn't surprise me because I had spent all night moving thousands of files around, and modifying partitions (including resizing the boot partition) I figured I'd corrupted something. So I put in the install DVD to try some repairs and it seems no distribution will boot from DVD either; iAtkos, Kalyway, Leo4Allv3... all 10.5.2, all hanging.

 

Kalyway hangs on:

com.apple.driver.ACPI_SMC_Platformplugin'' has immediate dependencies on com.apple.kernel and com.apple.kpi components use only one style''

 

The other two list the number of CPU cores and stop at:

 

ACPI CA 20051117 [debug level=0 layer=0]

 

All basically the first few seconds of attempted bootage... why?! Yesterday this all worked, apart from changes to OS X itself, no system modifications have been made. I rebooted several times yesterday, no problems. It's like it's suddenly become completely incompatible..

 

Any help greatly appreciated!! :mellow:

[Zoodogtrainer]

Start your computer with your windows OS, open COMMAND PROMPT, write DISKPART, write LIST DISK (you will see a list of disk with numbers), write SELECT DISK N (where N is your disk number where you'd install your MAC OS), then write LIST PARTITION, write SELECT PARTITION N (where N is your partition where you'd install MAC OS on the disk previously selected), write ACTIVE (this sets your partition as active), write EXIT, write EXIT, Reboot and good luck!