Trying to find out why my computer is so slow

1) You have a basic lack of RAM, a minimum these days is 8 GB. Prices are currently low, so now is your chance. It should have been done 5 years ago.

2) I see from your other posts you run a lot of stuff at the same time with a vast number of Browser windows open, this requires more RAM, swops to the HDD are slow which is what happens with lack of RAM.

3) If you are still using the original HDD then that probably wants replacement, at the minimum a surface scan to see exactly what condition it is in.

You seem to be confused with what the Task Manager is showing and getting far too many over technical replies which you probably don't follow.

You won't get different answers a year later, the same things apply. Quite basic things.

The symptoms you quote are most likely to be due to these 3 basic factors, possibly others, but you have to do the basics otherwise nothing will change.

I have seen many computers with "only" 4G of memory that runs very well.
If OP has Win 10 64 bits he can add more memory by adding one more 4G stick (if he has 4G+0) or replace with 4+4G if he has 2+2G.
Most of computers getting slow were from a problematic HDD (dying).
Going to wait for the results of the disk check.

Use Autoruns to see what 3rd party stuff is loading at startup and disable or uninstall stuff you don't need. Upgrade your HDD to a SSD which are quite cheap these days.