MacBook Pro won't recognize administrator name and password. Just installed the Remote Desktop Update. Could this have such an effect?

Thanks for replying. I'm sorry but I used the incorrect term. I have been typing in User name. I'm sure the User name and password I'm using are correct as they've always worked in the past. I tried a fix that I read in a thread here for a similar issue, which involved restarting the computer in a safe mode that opened the Utilities window. The steps I followed allowed me to set a password, so I entered the same password as before. I also checked to return the computer to default settings just in case I had inadvertently changed some setting that caused the log in issue, then restarted normally. Still doesn't work for me. In addition to not being able to unlock and change settings on the computer, I can't download a program from the internet. Thanks for any ideas you can offer.

I do not need to sign in when restarting the computer. I believe my account is administrator account but I'm not sure. My user name is the one that shows next to the Home icon. That's about all I know about this. I must tell you (in case you didn't notice!) that I'm not very computer savvy.