warez = pirated downloads (doesnt matter where from.. p2p, torrents, ftp.. all the same)
the no-cd is probably a rar file, you'll need rar to unrar it (
www.rarlabs.com)
unrar it, read the nfo (its a text file, so open it in notepad, or use 'view file' within winrar..) it will have the instructions...
generally all thats required is...
1. open the rar, see what files are in it (usually exe and nfo)
2. go to the game folder, find those files, rename them to .bak (therby making a backup.. which you might need later.. and will save you having to reinstall)
3. extract the files from the rar into the folder where you renamed the other files
4. (not always necessary but a good idea none the less) virus scan the game folder, to check the exe isn't virus packed etc... gcw does virus scan, but theres a possiblity some slip through and so on...
hope that helps
also, read the faq, it contains lots of help, definitions and notes