By doing this, identity thieves can learn about your personal information, such as account numbers, PINs, and passwords, and then use the information to gain access to your bank accounts and credit cards.  It is even possible for some identity thieves to gain enough information from your computer to open new, fraudulent accounts without your knowledge.  By using anti-virus and anti-spyware software, you can keep identity thieves from accessing any of your private documents that are stored on your computer.