Active Password-Field after boot

Hi,
formerly when i start vista, the password-filed was automatically activated
on the login screen and i just have to type my password to login. (there is
only one user on this computer)

Some weeks ago this changes. After booting the computer the password-field
is not activated. I have to use the mouse and click into the password-field
or i have to press ctrl-tab twice to active the password field. Then i can
type to password.
After booting the password-field is activated (i can see the cursor in it)
for some seconds but then the cursor disappears. It seems that another
application is starting and gets activated.
While pressing ctrl-tab i see 3 application but all have the same name.

How can i activate the password-field automatically after booting?
Thanks
Andi