I have a Lenovo Thinkpad and all of a sudden it was running slow. If you open the Task Manager and click on Performance and select the CPU it shows that the CPU’s Speed is at 0.4 GHz. No matter was settings you change in the BIOS or Power settings it will not change. According to Lenovo there was Windows update installed a new driver for the Intel Dynamic Tuning Technology software component. These are the steps to install the correct driver.

• Right click the Start button and open Device Manager.
• Locate the Intel Dynamic Tuning Technology device under Software Components.
• Uninstall the current driver from Device Manager, during the uninstall put a check mark to “Attempt to remove the driver for this device”
• Click on this link to download and Install the older driver: Intel Dynamic Tuning Technology Driver
• Restart the device.
• After installation, you need to prevent Windows from installing updates. You can do this by going to Settings / Windows Updates, then to the right of Pause Updates select 5 weeks. . Hopefully Microsoft will fix the update so that the next time it downloads it will not cause a problem.