hi my friend !
about youtube : open 2 explorer or mozila or whatever .
in one go to the movie you want to download and up on the "Address" copy the link [ctrl+c]; than go to the second browser and use to the address : www.keepvid.com than "enter" ; when the page is loaded just paste the lynk from youtube in the doanload aria and choos download from youtube than again enter .
underneth , down is gonna be a .flv file for download , click on it and start download . is gonna be opened with vlc player or any player wich support a flv file . have a nice day :)