I purchased this system used and I tbelieve it was used on a network domain. I am using it as a simple home system and want to add other family members as users but the system won't allow me. How can I over come this problem1 person needs an answerI do too

With a used computer, no matter its provenance, doing a clean install is best practice. This is particularly important in your case as there will be many domain settings tattooed on the computer which will make it difficult for you to use. Most laptops and many OEM (HP, Sony, etc.) desktop computers come with a factory restore image on a special partition on the hard drive. The factory restore process is normally invoked by pressing a Function key (like F11) at computer startup. There will be a message as to which Function key to press on the screen when you first start your computer. You can also refer to your computer manual, or the computer mftr.'s website, or contact its tech support to see how to restore your computer to factory condition since each computer mftr. does it differently - sometimes even between models. These machines also usually have a utility with which to create physical recovery discs in case the hard drive needs to be replaced or the factory restore image is somehow damaged. If you did not create the physical recovery discs and/or damaged the recovery image, contact the computer mftr.'s tech support to order a recovery disc set. This is normally very inexpensive, around $20-25. http://michaelstevenstech.com/cleanxpinstall.html - Clean Install How-To http://www.elephantboycomputers.com/page2.html#Reinstalling_Windows - What you will need on-hand MS-MVP - Elephant Boy Computers - Don't Panic!