Windows 10 stopped accepting my password.

[Thomas Aftanas]

I had a few problems with windows defender when windows 10 was installed. I had to restart windows a number of times. It always asked for a pin or security number. Now it asks for a password. I enter my password. I get the message the user name or password is incorrect.
I had microsoft reset my password twice. I still can't log into my computer. I'm the only user of this computer.