1. Stopping a program cannot do permanent damage no matter what. All you need to do is to power your computer off and on and they will restart.
2. Go into settings (or on a machine that old, TASK MANAGER). In particular, look at what is begin started automatically when you reboot. On current machines this will be in Task Manager / Startup. Chances are that there are a dozen or more programs that start the minute you reboot. Most of them are memory wasters.
In my cases, there are 13 on the list, but I disabled seven of them. (Right click on the program name, then select DISABLE on the pop-up)..
I can’t tell you which ones to disable because I don’t know which ones are on your PC. Do some homework on the list and see what’s important. Keep those enabled, and disable the rest.
Third (and scariest) there is a control panel section called Services (SERVICES.MSC) from the search box on the lower left.
This lists all of the services that can run. Some are active, some are disabled, and some are started on demand (unless they are disabled). A lot of them are Microsoft services that can’t be stopped.
Again, you need to do some research. For example, Windows Search is a pig of a program which takes a lot of memory. Disable it. (There are many other search softwares that are faster). Windows Backup is another memory hog. Disable it (and use something else for backup).
When all is said and done, you will probably disable a good dozen programs. SAVE your work and then reboot.