Use Super Antispyware to find out.
It has been reported before that a system restore kills the malware. There may still be some files left though. Be sure to run SAS in safe mode. It would be a good idea to use Ccleaner, too.
Install Super Antispyware free. Run it in safe mode. Allow it to quarantine whatever it finds. http://www.superantispyware.com/
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/
While installing Ccleaner you will be offered the Yahoo Toolbar. Be sure to uncheck it unless you want it.