Why do running programs and windows take a long time to respond to open ones, what is the reason for this?

Question

Iron

In general, the computer is old, 4 GB of ddr2 RAM and 4 1.8 cores. Works sometimes for several days. Previously, I sinned that there was not enough disk space. Freed up 9 GB. But everything remained almost the same, for example, if in the morning you start clicking on a computer that worked for a couple of days and a browser and a few more windows and word are running there, then it reacts for a very long time, but after a couple of minutes if you click all the windows, it starts working normally. There is a swap file. Is there any way to fix the situation so that there are no such hangs?