Be sure you install all windows updates. here's the site below
http://v4.windowsupdate.microsoft.com/en/default.asp
major stuff to install is the crucial updates. the other updates you make the decision if you want it or not.
also download Eplorer 6 service pack
after you are done install all programs that you have at home
i would reccomend that you install ( spybot s&d, adware, and bazooka scanner. once you are finish with all of this, now its time to run each program, one at a time. when you are finished running all these programs, i would also reccomend that you do diskcleanup, scandisk, and defrag. in this same order.