Everything was ok yesterday , but now i have seen that my CPU fan is running constantly at very high speed.

I tried restarting it. Before when i turn on the PC then fan used to run very high speed for 10-15 seconds then go back to normal.

But now right from beginning the speed remians very high.

  1. Can any virus do that
  2. if i remove some usb drives , can speed of fan be reduced

This is the image from my speedfan software

enter image description here

  • Could be a BIOS setting that changed somehow (BIOS update, battery run out, etc.), otherwise let your pc idle for few minutes, go to the task manager at the processes and short them by CPU usage and check whether there is a process that loads the CPU and report back. – Vagtepes Feb 22 '15 at 9:28

Some BIOSes have fan control options that can let you set the fan profile to automatic, passive, active, or even the exact RPM if you have a 4-pin header. Sometimes a BIOS update can screw up this setting or a power outage can cause a BIOS to forget its' settings.

~2500 RPM isn't too alarming depending on the size of the fan on your CPU. It's possible that the bearings are going bad so it will now always have a loud noise. Are you positive it's the CPU fan? The power supply also has a fan and I have mistaken its' loudness to a different fan in the past.

I am currently alarmed by the temp on HD3 to be honest.

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