boss i've already DL some games. i can extract some games but i can not extract some too, why is that??
Uhmm... what message did you get when extracting? Yep just like groh said, there's a high chance that your download is corrupted. Try downloading the file again with the help of download managers, it should minimize the number of corrupted downloads you'll get.
You should be using winRAR to extract the game. There are some extracting programs that don't do as good a job.