big trouble with mpg files

[iguana]

I have downloaded a couple of mpeg files,movies, but i cannot view them not on media player 9 nor on any other player.The problem is even worse ,when i try to view them the whole system slows down dramatically ,there is actually a creapy sound from laptop hard disk!It even crashes before i try to view them, when im in the folder that are saved and tries to make thumbnail!
i have the k-lite codec installed so i dont know what else to do
Does anyone have any idea what could be wrong?
thanks

Are they DivX? Try installing that if you haven't already.

How big are they?

Most importantly . . . are they pr0n? pr0n won't play on Windows XP.