Script problem on WIN XP...?

Every once in a while, an alert window will pop up like a JavaScript confirmation box. It says that the script running "on this page" might cause my computer to run slowly and do I want to continue running the script.

Thing is - I don't have any web browsers open. There are three other accounts on my computer, only one is logged-in but that other account doesn't have any web browsers open either.

I'm not running an active desktop or anything which runs scripting as far as I know. CTRL+ALT+DEL doesn't show any programs using more than 2% at a time, and I know all the programs which are running.

This started about a month ago, maybe a bit longer. The new software I've installed is:

OpenOffice

Yahoo Widgets

Yahoo Messenger (which is totally shut down when i'm not using it)

Any ideas? Could it be a trojan? I'm running Norton Internet Security 2007 with the latest updates and they haven't fouind a thing. Could it be spyware? Adware?

Script problem on WIN XP...?pop up blocker

Norton isn't any good,very few people use it any more.

Better,(much better),and Free is avg anti-virus.

"The Very Best" is nod32.They are the record holder for anti-virus.

You should be using Mozilla for a browser. One of their extensions is "No Script" works excellent!