Does the machine boot normally then give you the mesage or does it hang up?
What is the exact wording of the message?
What version of apple OS are you using?
So you are experiencing a Kernel Panic whichh is usualy received when you run a wrong version of OSX on your machine or have damaged the core files somehow.
Have you upgraded or changed your OS recently?
Let us know
Do you have your OSX disks or access to a different Mac?
Let me knowThanks
let me know if you can find an OS disk.
Could you put the disk into the machine and then reboot and as soon as you let go of the power button press and hold the C key till the apple logo appears.
Once it boot to the installer menu just go throught till you can open the Disk Utility window then select First aid and Click the Repair Disk button.
Let me know what happens or if you get an error.