How to make specific video filetypes recognized on its own?

windows 7 was do that good but i think after installing k-lite codecs with mpc association *.m4v & *.asf now i cant list them separately in explorer type column because *.m4v assigned under MP4 filetype & *.asf assigned under Windows Media Video filetype, so how to separate them again where i can select them under type column in search results without showing *.mp4 & *.wmv files
Answer #1
Control Panel\All Control Panel Items\Default Programs\Set Associations
Answer #2
here is what i mean so when i open Type column to select just m4v files i dont see the extension but when i select mp4 the results give me m4v with mp4 so how to separate them again so to be able to select each extension on its own??!!

EDIT: my god i cant belive i solve it i am very happy found a workaround i used Item Type instead yeeeeeeeeeeeeees!