For quite some time now (since the End of June to be precise), I have been annoyed by a loud rattling noise given off by the CPU fan in my laptop (OS: Windows 10) beginning at (almost every) startup and generally increasing in volume with every new application started, although the noise also varies randomly in volume and even disappears completely sometimes.
After cleaning the fan and dismissing dust as a possible culprit, I began to suspect a kind of virus as I noticed that whenever I viewed the Task Manager, the CPU utilization would be at something upwards of 50% even when no application was currently running. But a full scan of the entire hardrive when the fan was quiet for once with Kaspersky detected no threats. I currently see this as a normal occurence that is apparently merely typical to some CPU architectures.
Eventually I came across the advice of typing "sfc /scannow" into cmd to check for corrupted system files. And it worked... sort of.
The problem is that I basically have to type the command in regularly for my fan to stay quiet.
So far it has worked without failure for at least a few minutes before the rattling would eventually start again quietly before increasing in volume again. The scan always ends with "no corrupt files detected".
The CPU temperature as displayed by RealTemp stays relatively constant at 40°C, however.
Other things that only calmed the fan down for a short period of time:
-Installing moderately important windows updates
-Investigating the Event Viewer and following guides to solve error messages, particularly 10016 errors which pop up multiple times in one session