I forgot to tell how to find out the if it's 64-Bit when I mentioned it.
Simply right click on your "This PC" then Properties. It should be there in the System section. Or go to Windows setting thru the gear icon in the Win logo menu.
Unlike Mac, Windows still has memory leak. It could cause apps to hold RAM and never release it all when closed. But that's another story. However, do you get the problem upon starting up or after sometimes? Filling Windows with apps could be reserving (if upon start up) or holding (if after sometime) RAM at some point making Windows use Pagefile (storage for RAM).
It is common to have fresh installed Windows work great for some time then slowing down later specially on low specs.
Keep in mind that such problems are difficult to diagnose without seeing the computer. Good luck!
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