Hi Dmitry,
If you mean like 'have I installed packs such as k-lite, etc.' then no. But I have installed a couple of converters (Daniusoft, Super) and I have trial versions of Replay Media Catcher and Media Converter - not sure but don't they come with codecs? Also, when I play some videos via WMP I sometimes see the message 'acquiring codec' so as you can probably tell by now I do not really know how to answer your question.
I did a bit of reading on how to find out what codecs are in my pc and saw the how-to instructions via control panel, etc. Here's a list of the audio and video codecs that were listed:
Audio Codecs:
IMA ADPCM Audio CODEC
Microsoft ADPCM Audio CODEC
Microsoft CCITT G.711 Audio CODEC
Microsoft GSM 6.10 Audio CODEC
DSP Group TrueSpeech[TM] Audio CODEC
msg723.acm
Windows Media Audio
Spiro Lab Telecom Audio Codec
Fraunhofer IIS MPEG Layer-3 Codec
Dvcam.acm
Microsoft PCM Converter
Video Codecs:
camcodec.dll
Cinepak Codec by Radius Inc.
DivX 6.8.5 Codec
i420vfw.dll
Indeo codec by Intel
iyuv_32.dll
Microsoft RLE Codec
Microsoft Video 2
msh261.drv
msh263.drv
msyuv.dll
tsbyuv.dll
yv12vfw.dll