I have a Dell Dimension laptop that still runs on Vista. After downloading and running an older version of Opera Browser from a third party, I noticed the laptop’s internal fan was running at high speed. Something overheated and caused a shutdown. Removing the program and all of its components, using System Restore, CCleaner, Malwarebytes and Avast help somewhat but the PC still goes into high-speed fan operation many times. All virus and malware scans were negative. Is there any way I can check the CPU’s clock speed and reduce it if necessary?