Password not working

I have windows xp sp2 system, everything was fine until yesterday when the password started not working, when ever i restart my computer it directly logs in not showing the password screen:-o , i feel very unsecure coz there are lots of porn videos and other stuff in my computer, though no one expect me uses my computer but still afraid of end result:-o , why is this happening why it isn't asking for password and logging in directly:cry

 

Try Start>Run>type in control userpasswords2 and hit enter.

Make sure the box for "Users must enter a user name and password to use this computer." is checked. If not then check the box and hit Apply button. Don't change anything else and close the window.

 

It seems to me that if you have lots of porn and other stuff on your computer as you mentioned, it may be wise to go to the Malware Removal Forum and see if you are infected.