My computer (WinXP) has acquired an unwanted toolbar. It sits under IE, has a small search field and then an array of radio buttons with changing topics such as "Pay per click, Homepage" etc.
When I right click this tool bar a drop down list from 'View" appears; at the bottom of the list is the entry 'bike', and it's checked. Unchecking it temporarily closes the tool bar.

Any info on how my PC acquired this, and especially how to get rid of it is much appreciated.