I downloaded flashback removal tool can i run it i have os x 10.7.3
Limnos is absolutely correct, you did not need to download the tool separately from what Software Update ask you to do. Also, if you installed it then you did run it and it either told you that it removed something or it didn't tell you anything, meaning it didn't find anything. After which it deleted itself.
Open System Preferences -> Software Update, and click the Installed Software tab. Look for either "Flashback malware removal tool" or "Java for OS X Lion 2012-003". If you see either of those (only one will be there, not both), the malware removal has already run, and then tightened up security on your machine to ensure you don't get infected again.