Install uTorrent and use one of the following sites to search for a game:
The Pirate Bay - based in Sweden. These guys are politically active against copyright.
Isohunt - A site based out of Canada, probably the largest torrent search engine out there.
You will find 98% of what you are looking for on these sites. These sites don't actually offer the game, instead they distribute Torrent files. Torrent files don't contain any software in them. They merely point you to people who have a copy of the software. You can then ask those people for pieces of the file. While you are building your copy piece by piece, others will ask you for pieces of the same file. It is in this way that files are shared. You are distributing tiny pieces of the greater file at the same time as you are receiving tiny pieces, eventually everyone helps each other build a complete copy of the file.
Those people who have a complete copy of the file are called "Seeders" and those who are in the process of building a complete copy are called "Leachers". The more seeders there are for a file, the more popular. These files will tend to download faster and be more likely to work properly. Leachers can also have an impact on transfer speeds, avoid files that have hundreds of times more leachers then seeders. This could indicate many people competing for the last fragments of a file from a small number of slow seeders. Both the Pirate Bay and Isohunt allow you to sort their lists by seeders, and I recommend doing that.
When downloading a torrent file be sure to have windows open it with uTorrent. uTorrent will then start downloading pieces of the actual game. This could take some time. Modern games are anywheres from a half a gigabyte to ten gigabytes long. This can take the better part of a day even on a good broadband connection.
When the transfer is complete, uTorrent will go from leaching the file to seeding it. You can continue to seed for as long as you want. This will help all those who are still getting their copy. In fact when people download more then they upload it makes for more work for everyone else trying to get the file. Most people using torrent consider people who seed less then they leach scumbags of sorts, but of course, they'll never know you.
If your completed file is a .zip or .rar file you will need to uncompress it. Use Winrar for this. It is a trial software, but it will let you use it forever with a nag screen. Just right click the file and select 'extract files', then show Winrar where you want the files. If you don't know what you are doing just open a folder on your desktop (right click on desktop, select new, select folder) and extract the files there.
Most games will be in image formats. These are CD or DVD image files that contain a bit by bit copy of a physical disk that is saved on your hard drive. You will use Deamon Tools Lite to access these disk images. Deamon Tools is a program that emulates a CD or DVD rom drive. Instead of optical disks, Deamon Tools uses disk images and fools Windows into thinking they are real disks. Disk images are in many different formats .iso and .bin files are common, but there are also .mdl and .img files. Deamon tools should be able to open all of these. just right click, open with, and make sure windows uses Deamon Tools to open.
From here on the game should install as if you were using real disks. simply follow the prompts from the game installer. If you need to swap disks simply find the file for the next disk and open it with Deamon Tools and it will replace the current image with the next image.
Most PC games utilize some form of copy protection to keep people from pirating them. The most common protection is a form of software that can detect whether you are using a real physical disk or a home-burned disk or disk image. This software and other techniques to curb piracy are collectively known as DRM, Digital Rights Management. These added programs run undetected in the background briefly when you first run a game. DRM doesn't work, and it only punishes those who buy their copies legally. Some forms of DRM are particularly draconian. EA game's Spore actually would not allow you to install it more then 5 times. They would keep track of how many times you installed and deny you your game if you went over your allotted installs. This DRM was removed after public outcry, but it never really stopped the pirates.
Now that you have your game installed you will simply have to remove the DRM that prevents you from running the game. Deamon tools may be able to do this because it can emulate an actual CD/DVD pretty good, but there is a better way:
GameCopyWorld - This site is an archive of hacked game files that will allow you to play without the Physical disk. These files are called noCD cracks or fixes. They are completely legal for people with legitimate copies of games who don't want to mess about with optical disks. The best part of GameCopyWorld is it contains up to date versions of most games. When you update or patch a game over the Internet the DRM will be reinstalled. You will have to find an updated crack every time you update. GameCopyWorld is pretty good about keeping their archive up to date, and that means you can take advantage of all the latest features and bug fixes for your game.
I would recommend checking the Internet for the latest patch or update for your game before cracking it. Do this by finding the game's official site, and download the patch from there. Be sure to note the latest version number. Then search for the latest crack on GameCopyWorld.
NoCD cracks tend to be a simple .exe file. This file must replace the exact same file that is present in the game's directory. Using Winrar, extract the file into the game's directory, and make sure to replace the old file with the new cracked file.
That's the basics. There are a lot more tricks that you will just have to discover on your own I think. I'm getting too tired to go on much further. I may edit this later and add some pictures, maybe make it more comprehensive. There is a trade off for free games. Sometimes you will have to spend a lot of time tinkering to get things to work right. The technique I have described will work 90% of the time though.
Leave a comment if you a have any questions.