|Your laptop is in fact possibly infected by a virus.|
Even if you have an antivirus software installed, your system can get infected, cause it always appears, first a virus is spread out and after that, an antidote will be developed.
In doubt, download and burn one of the below listed windows independent antivirus boot cd's (ISO), boot the laptop with it and check your system for viruses.
Avira AntiVir Rescue System
Kaspersky Rescue Disk 10