[newbie] turn off computer?

[Andy Yankovich]

Hi guys, My computer is used only by me. Never by another person. I have a cable connection that is always on. 1. Is the recommended procedure to turn computers off at least nightly or keep them on all the time? 2. Should I install some type of firewall for security reasons? I do not have any secret formula for Coca Cola or things like that on my system, but do have credit card and other financial info, If yes, what do you recommend? 3. Ditto for anti-virus? If yes, what do you recommend? 4. Is the anti-span feature built into KMail sufficient or should I pick a second program. If yes, what do you recommend? Looking forward to both your answers and *reasons*. Andy