Have you tried a spyware program? Ad-aware is a good one and it's free and very easy to use.
I have a Dell 3000 using windows xp. When I connect to internet I get a solicitation from popcorn.net. I can only close by going to task manager and finding "notifier.exe" (application) on the list and selecting End Now. I did a file search and found it, but can't delete it because "it is being used by another program" How can I stop this beast? Thanks for any forthcoming advise.