First check if your PC is really infected. For this you can submit Zorro.exe to a scan service like https://www.virustotal.com.

If your PC is infected, please stop all work, reboot it from a clean media, and run a thorough virus check with a serious tool (not Security Essentials). Then download and install Zorro again.

- Update: We got similar reports from other users and have informed Microsoft of this incident.