this is what sounds like a trojan or for of spyware, probably disguised as a screen saver.
If you have no anti virus installed download this programme for free
http://free.grisoft.com/doc/5390/lng/us/...If you have no anti spyware programme download this for free.
http://www.download.com/Ad-Aware-SE-Pers...on the laptop press Ctrl, Alt & delete or right click on task bar to get to the task manager and on the processes tab look for the scrensaver.exe or similair that is running, click on it and press end process.
this should allow you to work with windows
Install the programmes, then go to system restore tab in my computer>right click>properties>system restore tab and click 'turn off system restore'(this will stop any virus or spyware backups reinstalling).
Run both the programmes and remove any spyware or virus.
If it still appears you may have to uninstall it safe mode, which is press F8 key on start up and select 'start windows in safe mode' and run the antivirus and spyware programmes again.