If a virus is replicant (coming and coming again), you should:

  1. Disable System Restore on Windows XP: http://support.microsoft.com/default.aspx?scid=kb;[LN];310405
  2. Clean your temporary files.
  3. Schedule a boot time scanning with avast. Start avast! > Right click the skin > Schedule a boot-time scanning. Select for scanning archives. Boot.
  4. Download, install, update and run other trojan remover tools:
    a-squared
    Free AVG Antispyware
    SUPERantispyware
    Spyware Terminator