The easiest way is to run Regedit and do a search for the previous owners name. Everywhere the previous owner's name pops up just edit it and enter yours.

Thank you so much, but how do I find that?  This is all so new to me.  Thanks for you help.

Rhonda

goto Start/Run: type REGEDIT.  if you are not familiar with this function, don't change anything other then the name. 

What OS are you running on your machine?  if windows xp, you can change the user account through the control panel.