gurus out there please help...
am experiencing this annoying pop out doctor antivirus warning from my kids lappy and saying it has detected harmful or potentially dangerous viruses and spyware.

guess one of my kid tried to install this doctor antivirus but retreated when prompted with the buy or register prompt. also tried with same result. please help how to get rid of this annoying on and off warning! can't find from the installed programs either

btw, AVG antivirus free version and spyware doctor were installed on their lappy. tia