Cannot Enter A Password On Logon Screen

I have recently set a password for my administrator account because some
relatives were coming over and i didnt want them to muck around with
computer. I then tried logging on and i cannot enter my password. It displays
a picture of a chessboard and the word administrator underneath. it then has
the word password in smaller letters below and a little to the left. when i
move the cursor around the screen it changes from an arrow point to a hand
around the picture. I have tried clicking on there but no box opens for me to
enter my password.

If anyone can help it would be greatly appreciated.

Regards Andrew