i believe it is spyware, web rebates is a classic one i have just finished cleaning up a pc for a friend who purchased it second user and it was full of it, i always use lavasoft adaware http://www.lavasoftusa.com/support/download/ first and then spybot search and destroy after http://www.safer-networking.org/en/download/index.html after downloading and installing them check for updates before running them so they have the latest definitions .