Antivirus blocked in the center of the screen

I have windows XP with 1 GB RAM. My antivirus software (Panda Cloud Antivirus Free Edition 1.5) is shown in the center of my monitor. It does not close and half of the screen is blocked by it. I can work on its sides but not the place where it is shown. I tried to cancel it but it would not cancel. How can i resolve this?
