AVG AntiVirus Free Edition
This is an antivirus and antispyware protection for Windows and it's available to 
   download for free.   
   BitDefender 10 Free Edition
   Bitdefender is a free virus removal download
   McAfee Conficker Removal
  Scan your computer for free and see if you have any conficker infection on your system.
   Microsoft Virus Removal Tool
  This tool will detect and remove virus infections on your computer.  It is also free!
   What is a Virus?
   A virus is developed to attach itself to software so that it can it can infect your system when
   you install the software.  It is usually very malicious and it damages computer operating
   systems and sometimes reformats hard drives.  These various free virus removal tools are a
   safe way of removing these threats.  It is important to scan your system regularly.
   Remember not to use just any virus removal downloads.  Many of these downloads will
   infect your system.