Personal Computer Use

I use the computer for work, school, as well as personal use. At work I use Micrsoft Outlook to send and recieve emails. I also use SAP system at work to enter and retrieve information on various jobs. I take online classes so I have to log into class throughout the week and complete assignments for school. For personal use I use my computer to look up weather, news, scores for various sport, and much more. I do use the computer to keep in touch with people I know via sites like Myspace and Facebook. At home I have a high speed DSL internet connection that I have a wireless router on so that I can do my work anywhere in the house on my laptop. I would like to know how to keep my computer running at optimal performance.
Usually when I get on my computer I check my email then look at the news and weather followed by Myspace and Facebook. I do not believe I am capable of maintaining my own software and hardware. I did install an anti virus and have ran spybot and adaware on my computer before so I can take care of virus prevention but am incapable of fixing my computer once a virus is in it. I do know how to upgrade my hard drive and add more RAM to my computer, however I have not done this since 2002 on my last computer. I am not the only one that uses my computer, my wife will use my laptop when it is convenient for her. My wife is much better than me on the computer. She uses many of the microsoft office programs at work and I mainly use SAP when at work. My daughter is 5 and she only plays some educational games on the computer but she uses the pc and not my laptop. I use the computer quite a bit throughout the day but am learning that I was not aware of its full capability.