|If you feel the computer is slow now and was fast when new then it might be time for a complete reload of the OS. Be sure you know how to recover all important data and programs before you attempt this.|
Good advice on using the home router to help firewall the system. Be sure to have a good security suite on it, at least microsoft's security essentials. Consider a good hosts file too.
1/3 of highway deaths are caused by drunks. The rest are by people who can't drive any better than a drunk.