Hi Michelle,
I'm Christine, looks like your mother is getting a notification saying her computer has be disabled by Windows Defender. No worries, I got your back!
This notification is a scam attempt, please do not call that number. Please take note that Microsoft will not include phone number on their error messages.
For your reference:
https://support.microsoft.com/en-us/topic/avoid...
I will suggest you to clear the cache and cookies to delete that error message on your browser.
If you are using MS Edge, please press CTRL+SHIFT+DEL and set the Time Rage to 24 hours and hit Clear Now.
If you're having issue closing the browser, please press CTRL+SHIFT+ESC and you can end the browser from the task manager.
Please let me know the result. I'll be happy to assist you all the way until it's resolved.
Thank you,
Christine L
Independent Advisor