1. Start Counter-Strike: Source and in the menu screen of the game go to "Options". In the "Options" window click on the "Video" tab. Below the "Display Mode" text there will be a drop down bar. Click on it and select "Run in a window". Click "OK".
2. While in steam go to your "Library", right click on Counter-Strike: Source and go to "Properties". In the "Properties" window click on "Set Launch Options" (it's located in the "General" tab). In the "Launch Options" window type in "-sw" (without the quotes). Click "OK".
Happy fragging.
