Stopping program install function

I have done something (XP) that has realplayer convinced that it should install. I guess I clicked on some site that required it to play a particular file.

I don't want it to (well, I don't need it and didn't intend to install it), but it keeps turning up with "Retry and Cancel" options every time I boot up. I don't know why this is happening, but I'd like it to stop trying to install since it is failing to do so. Retry doesn't seem to change anything. How do I remove this attempted installation since it's not working.