Locked out of administrator account username

Hello

Please help me.
I have an Ibook G4.
I have two user accounts mine (administrator) and a very restricted basic.
Everytime I log on it goes straight to basic and I usually log out and into administrator.
Last night i installed norton antivirus on it.
I had to log out before I set it up.
So I started off in basic I then tried to log on to administrator but when I typed in username no letters came up.
So I went back into basic and turned of norton.
And logged in to administrator.

Today my computer crashed a I think I had too many things running and was scanning for viruses with norton.

Now when I log on to administrator the username cannot be typed again.

Im stuck in basic. I cannot open my accounts on systems preferences as it is blocked by the adminstrator account.( it doesnt even ask for password its just a no go).

I have deleted Norton from my basic but no change.

I have all my important files and invaluable photos in my administrator account.

Can anyone help me?

Thankyou.

Thanks for the reply but Im sorry Im not very familiar with macs, I did this but bothing changed. I dont understand. What do I do next?
Thanks

Does this require me to go into systems and then accounts as I cannot.
I did the verify disk permission but I dont know what that does or what I am meant to do next.
Thankyou

Does anyone have any ideas.