Hi Helen,
Welcome to our forum!
What do you mean about your programs? Office Apps or System or something else?
If you mean you don’t want others to access the files create by your Office App, please refer to the article: Limit sharing in Microsoft 365 | Microsoft Learn
If you mean you don’t want others to access the system or files in your system, you may want to refer to the methods Angela Pun.
Provided in the thread reset all permissions for windows 10 and remove any unwanted hidden - Microsoft Community and have a try.
Hope it helps.
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