There's lots of info on the web about this particular one. I went to one site that had lots of good advice about how not to get it but I can't remember the URL and can't seem to pick it out after a search now. The gist of it was to always select custom or advanced if you download something from the web and install it on your computer. This tends to be a tag-a-long program that in some cases you can unselect when you don't use the default install.
If you keep getting it back, then it should be easy to determine where you are getting it.