How to get rid of the "WEBCAST" in the internet explorer toolbars

I want to know how to get rid of the "WEBCAST in the internet explorer toolbars. Few days ago I wanted to download a mp3 song but unfortunately I don't know what I had I done maybe I had download something that bring virus because my internet explorer toolbars added one extra toolbar called "WEBCAST" and when I browse the internet when the internet is not connected , the browser should display the "cannot find server" but now the browser instead of display the "cannot find server" page, the browser display "search the web-incorrect page error" together with the extra toolbar called "WEBCAST" and pop up windows consist of Javascript.

According to the location of the page is in C:\Documents and Setting....\Temp\compErrormeet.htm
but, when I try to delete the "Temp" folder, the folder cannot be deleted.
I am scared that it is actually a virus inside my computer. It that a virus??
What should I suppose to do??? I want my internet explorer display the "cannot find server" page when the internet is not connected and I don't want the "WEBCAST" toolbar.