It was just in your system restore point. SAS caught it, bbut you might want to create a new clean point and remove the others.

Create a new restore point

You must be logged on to an administrator account
Go to Start - All Programs - Accessories - System Tools System Restore.
Click Create a restore point, and then click Next.
In the text box labeled Restore Point Description, type a name for this restore point

Remove old restore points

Disk Cleanup - Launch the Disk Cleanup tool and then select the more options tab. On this tab you will find a section for System Restore. If you press the Clean Up button for that section, Windows will delete all restore points except for the most recent one.