With a Win10 PC, you're almost always going to experience a very slow PC at times because Windows Update (WU) is hogging your PC, searching for, downloading, and installing updates -- to bring your PC up to the most current version of Windows.
And, when it does that, it can force the disk usage to 100% and drive up the processor load -- and keep them both pinned there for some time. That can cause the fan to run loud and continuous for some time.
This process is complicated by new Win 10 patches coming out nearly every Tuesday -- as one did last week.
Some folks have been told that resetting your PC will fix this. but, if you reset your PC, you only make matters WORSE! Why? Because you will reset Win10 back to the original version that came preloaded on the PC and that will restart Windows Update all over again.
To find out what version and build of Win10 your PC is running, do the following:
1) enter "cmd" (without the quotes) into the search area and select the Command Prompt option
2) enter "winver" into the command window (again, without the quotes)
3) the most current Win10 version (as of 4/2/19) is v1809 Build 17763.404
If yours is older than that, most likely WU is hogging your PC trying to update it.
To disable WU temporarily, do the following:
1) Enter "services" in the search area (again, without the quotes)
2) When the window opens, scroll down until you see Windows Update
3) If it say Running under status, that indicates that WU is running
4) To change that, double-click on that task, select Stop under the Service status, and then Apply
5) That should stop WU -- and you should see an immediate improvement in performance
If not, then WU is not the problem.
WU will restart itself automatically later on, so you basically have no choice than to bear with it until it finishes.
As to quieting the fan, no, there is no way to do that.