password sign in to windows

When I start windows I see 3 or 4 users. I'm afraid to delete any instance of these for fear of deleting something I don't want to delete. The default user is the wrong one so I move the cursor to the correct one. It asks me to sign in. My Sign-in options tells me I don't have a password. I have often gone to the user accounts and asked for NO password. It has no effect. I'm lost. I don't know why this has to be this complicated after all these years microsoft has had to work this system.

 

"Generally" your computer will have an Administrator account, an account with your own name on it and a guest account. We really need more information.
Hit the Windows key + R and then type in netplwiz and hit ok. This will bring up a box with user accounts. Take a screen shot of this and post it here.