I keep getting a pop up by norton saying

Norton AntiVirus has detectected and removed a viruis from your computer.

Object name c:\Program Files\Norton....\AP0.htm
Virus Name Downloader
Action Taken the file was automatically deleted

I click ok at this pop up and then it just comes back.
It alternates between AP0.htm and AP1.htm

I have ran AVG, I get no threats and I ran search and destroy sypbot, no threats, I have ran CCleaner....

Still it comes up, please help, driving me mad.