Hope you haven't caught this bug:
zCodec is a Trojan
Do not download
By Nick Farrell: Tuesday 05 September 2006, 09:12
SECURITY OUTFIT Panda software says that a video codec which is appearing in the wild offering "up to 40 percent better video quality" is a nasty bit of adware.
zCodec is freely available online and can be downloaded here. The site uses images from flicks Sin City and Pulp Fiction to claim boosts to audio as well as video quality.
It claims to be a multimedia compressor/decompressor which registers into the Windows collection of multimedia drivers and integrates with any application using DirectShow and Microsoft Video for Windows.
The only thing that suggests that there might be something wrong is a typo on the front page which links to its "terms of use" page. Still, you get that with the big jobs.
However, Panda said that the ‘codec’ downloads and runs files, changes the DNS configuration and monitors accesses to several adult websites.
It is known as adware/ZCodec or Adware/EMediacodec and affects most versions of Windows. Some of the files that the adware has been downloading are particularly nasty, including a rootkit called Ruins.MB, which does what it says on the tin.