1. Go to About this mac under the apple in the upper left and click on More info
2. Click on system report
3. make a note of what it says after Model Identifier
4. go to your master drive System -Library Extensions IOPlatformPluginFamily.kext -Contents Plugins ACPI_SMC_PlatformPlugin.kext Contents Resources find the name from step 3 and move it to a folder that you can find again if needed.
5. Restart and youre done