Combined Community Codec Pack isn't a normal codec pack. This pack guarantees there will be no conflict between installed elements and your system.
To do this, Combined Community Codec Pack (CCCP) automatically detects and tells you if there is a component or element that could be in conflict with some of the codecs you are going to install. This often happens when you have various older codec packs installed, and some of them can have an older version or one that's incompatible with some specific codec. In this case, the program asks for confirmation to delete it.
The codecs you can obtain on installing Combined Community Codec Pack are: Haali Media Splitter (MKV, MP4, OGM, AVI), VSFilter (SSA/ASS, SRT, VOBSUB Subtitles), ffdshow CCCP builds (H.264/AVC, DivX, XviD), WMV9VCM (codecs Windows Media), Media Player Classic and Zoom Player Standard.