Facebook is now redirecting users that have infected computers to websites where they can get free antivirus software. The Malware Checkpoint for Facebook will send people either to sign up for Microsoft Security Essentials or McAfee Scan and Repair. Mac users are sent to Apple Security Updates site.
If you want to know whether your computer is infected by malware, you can visit: http://on.fb.me/infectedMSE or http://on.fb.me/infectedMcA to become self-enrolled.
1. The McAfee option will download a small program onto your Windows computer to perform a one-time scan of your system for malware. It will not interfere with your existing anti-virus or other security products. After it scans your system, it will give you the option to automatically or manually remove the files it flags as malicious.
2. The Microsoft Security Essentials option is a full anti-virus product. Upon download and install, it will add anti-virus software to your computer that will continue to protect your system with the latest anti-virus signatures from Microsoft.