Installing Windows XP automatically writes over and deletes Windows 2000. It will not, however, write over or delete your files. It is safe, simple and painless. Having said that I want to mention that it is always prudent to back-up all your files and data before making major changes to your operating system. I would copy not only the contents of My Documents and My Pictures, but I would also copy my Internet Explorer Favorites (bookmarks) list, my Outlook or Outlook Express address book and my saved emails. That is only a precaution. I have been usuing and installing and working with Windows operating systems since Windows was first introduced and I would feel very comfortable installing XP over 2000. The process is automatic and very user-friendly. Here is a link to the XP home page at Microsoft. It will answer any remaining questions you may have: http://www.microsoft.com/windowsxp/default.mspx