Super Antispyware has had success removing Smitfraud malware.
It is also suggested to use it to remove the malware that often accompanies the Smitfraud malware.
Install Super Antispyware free. Run it in safe mode. Allow it to quarantine whatever it finds. http://www.superantispyware.com/
How to Start Windows in Safe Mode:http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
After removing the malware you should remove infected restore points. Directions in link below. http://www.bleepingcomputer.com/tutorials/windows-xp-system-restore-guide/
Remove temporary files, logs, cookies, etc. by using Ccleaner. Do not use "Advanced Settings" or the "Issues" button. Use only the default settings. http://www.ccleaner.com/
During installation you will be offered the Yahoo Toolbar---UNcheck if you don't want it.