Many people aren't even really sure what they need.  Most see how much fun their friends and family are having on computers, and want to do the same but don't know how.  Computers you buy in the store are very general.  They usually have a little bit of everything, just in case you decide you need to use it.  The truth is, you might be buying a computer with hardware that's above and beyond what you'll ever need.  When I build a computer, I only put in components that you'll actually need.  Whether you're someone who just wants to surf the net, play video games, or render 3-d animation, I can adjust to your needs.