Are you running Windows 10?

Have you confirmed which update is running?

Then, using that search window in the task bar, type in:

Turn Windows Features On

See the pop up for Open; Click it.

Checkmark that .net there, if it is not already enabled.

Now check for Windows Updates.

This is "care and feeding" of computers. All users should be able to keep their system basically updated. It's like your Car. Do you have someone come over and fill the tank for you, or do you go to the gas station yourself?