CPU Speed set to Compatible

Problem: A user reported that his machine was running very slow after taking a power surge. I observed that the CPU usage was pegged to 100%, but memory usage was down near zero. I also noted that there were no unusual tasks running, so I decided to run hardware diagnostics. The Dell diagnostics quickly produced an Error Code 0700:0120, msg: No cache detected. Cache might be disabled, defective or not present. Immediately after this error, I got a System Error! msg: System_Error illegal attempt to disable Intel CH SMI without restoring original values first...... Time to look at the BIOS settings.

Solution:
I expected to find that some of the devices were not even detected, but all seemed to be there. I compared the BIOS settings on an identical machine and found several settings that were different. I won't give all the details; the one setting that was causing the problem was: the CPU Speed was set to "Compatible" on the bad machine. I reset it to "Normal" and let the machine boot. Back in business.