trojan, spyware or what?

Hi, I'm trying to help out a work mate who has clicked on something he shouldn't. every time he goes onto the web no matter waht address he puts in it always takes him to the same webpage which is something to do with internet security. He says he has checked the site with Norton and is told it is a bogus site.  He has run spybot and adaware and also the normal checks with Norton but nothing shows up in the system as a trojan etc.  Has anyone come across this before, what should I advise him to do next?  Apologies for being a bit vague but under questioning he wasn't really sure what he was doing.