The pirated copies of Windows 7 that are circulating in bitorrent tracking sites have Trojan in them.

“Just a warning for anyone downloading the new RC builds of windows 7. Quiet [sic] a lot of the downloads have a trojan inbedded [sic] in the setup EXE. The Setup EXE is actually a container, it appears to be a self-extracting EXE. There are 2 files inside, Setup.exe and codec.exe,” said a user in Neowin.net’s forum.

The codec.exe is identified as a Trojan by the user’s antivirus software.

Source: COMPUTERWORLD