Blank pop up when closing Internet Explorer

I get a blank pop up window when I close Internet Explorer.It is from a web site named funcionamiento-con-la-tijera.com/go.php? . My computer was infected with w32.spybot.worm a couple of months ago.It was detected by norton antivirus. I went through the entire removal procedure and everything went ok. no more virus per norton. Is this a left over from the virus? Is this a web site the virus uses to run the virus? How do I get rid of it? I have seached the computer and deleted any referance to this site, Registry, temp internet files,etc. I have set firewall , internet explorer and windows security to block pop up from this site. Nothing works.The computer is running fine other than this anoying pop up. My operating system is Windows XP, with service pack 2. Thanks any help would be great.