Norton Does Not Support The Repair Feature - Malware

I have two problems that I think are connected. Every time I turn on my computer and log into my account on Windows I get between one and three error messages that say, "Norton does not support the repair feature, please uninstall and reinstall." I thought at first this was stopping some needed application, but the more it happened and from reading Norton's alert logs, I think it is malware trying to repair itself and Norton is stopping it. The alert logs say something about a Trojan Horse everytime I turn my computer on. In addition, if I go online as soon as I log onto Windows then it says that a "recent attempt to attack my computer was blocked." - I think this is related to the error message and Trojan horse