missing video codecs

so you see, yesterday was tiring but productive, i got myself enrolled for the first sem, paid the apartment, downloaded dead fantasy 1 and 2, printed New Moon, and got the complete series of Ouran Highschol Host Club (at the cost of 4gigs which nearly robbed my player all its storage space).

but i can't play the series with our player! i gathered that some video coded is missing! at first i downloaded media player classic because that's what astra uses to play vids but an error popped out saying they can't play it blah blah... because i don't have the supporting video codec for it.

i don't know what the heck a CODEC is. but i'm learning, i'm currently downloading K-lite Codec Pack... hope it helps. specifically i just need an xVid codec but whatever. i'm crossing my fingers on it! T___T;