Emcodec.b pretends to be an installer for Media Codec, which is a fake codec for Windows Media Player. However, it is also a trojan that drops a widely spread parasite related to SpywareQuake and SpyFalcon infections. Once executed, the threat displays the setup screen. Then it installs itself to the system along with another parasite. After a while, Emocdec.b executes that parasite and deletes some of its own files.