Microsoft Error: 0x00759B ???

I'm sure you tried rebooting, right?
You also might try a program called Malwarebytes.org which worked for me but I have Windows 7.
You might also do a Google search for `Windows 10 malware'.
This is while you are waiting for a pro to give you the real answer.
Sorry, didn't read the answer of doing a Google search to track the error code and how to get rid of it.

Phishing attempt to get your ID. You don't provide much info as far as when it comes up, what it comes up in, and how you've been able to close it. Don't reply, and get rid of the hijacker.

Do a google search for the error, you may need to take out the ":" but it is a scam and indicates you have some malware.

DO NOT GIVE ANYONE YOUR USERNAME AND PASSWORD! This sounds like a scam to me. At any rate, once they get your username and password, you have lost control of your machine. I am not sure how Win 10 works as far as going into safe mode and deleting startups but I am sure others on here will be able to help.