Hi- OK, so the Companion is still trying to launch. That may be because it was loaded and running when you uninstalled 8.0, I dont know, some programs do leave things behind one way or the other. Can't really say if it was designed to uninstall with AOL 8.0, or remain behind, only they can tell you. It does not have any uninstaller, so I gave you directions to turn it off, as it appeared that it was still launching, you did not say it was creating errors or anything.
I see in Program Files that the Companion folder is separate, and located just beneath the AOL 8.0 folder. I have never uninstalled 8.0, so I can only tell you that usually, you can stop any program from launching by renaming it's .exe file to, say, xxxxxxx.old- that is the only safe thing you can do for now. Unless someone comes along who has sufficient Registry experience and feels confident that they can guide you through a Registry removal of the Companion, if you delete the folder you would probably have a big .dll mess, since the rest of the Companion "Applet" let's call it consists of just .dll files.
It does appear in msconfig, under Startups, I am wondering if you looked for it? It might still be there, and you can simply turn it off from launching when WINDOWS does....I have done this, and it does not try to launch when I start AOL 7.0.